Processes for preparing metallocene-based catalyst systems in cyclohexene

ABSTRACT

Methods for preparing metallocene-based catalyst systems containing an activator-support are disclosed. These methods are directed to contacting an activator-support, an organoaluminum compound, and a mixture containing a metallocene compound and cyclohexene or a mixture of cyclohexane and 1-hexene, resulting in catalyst systems with increased catalytic activity for the polymerization of olefins.

FIELD OF THE INVENTION

The present disclosure concerns metallocene catalyst systems, and moreparticularly relates to homogeneous solutions containing a metallocenecomponent and cyclohexene, useful in preparing olefin-based polymers.

BACKGROUND OF THE INVENTION

There are various methods used to prepare metallocene-based catalystsystems containing an activator-support. These catalyst systems can beused to polymerize olefins to produce olefin-based polymers, such asethylene/α-olefin copolymers. For the same initial components of thecatalyst system, it would be beneficial for these catalyst systems tohave higher catalyst activities and to produce polymers having lessresidual solvents, as a result of the method used to prepare thecatalyst system. Accordingly, it is to these ends that the presentdisclosure is directed.

SUMMARY OF THE INVENTION

The present invention generally relates to new catalyst compositions,methods for preparing catalyst compositions, methods for using thecatalyst compositions to polymerize olefins, the polymer resins producedusing such catalyst compositions, and articles produced using thesepolymer resins. In particular, the present invention relates to methodsfor preparing metallocene-based catalyst compositions, and to theresultant catalyst compositions. Catalyst compositions of the presentinvention can be used to produce, for example, ethylene-basedhomopolymers and copolymers.

Various processes and methods related to the preparation ofmetallocene-based catalyst compositions are disclosed herein. In oneembodiment, a process for producing a catalyst composition is providedherein, and in this embodiment, the process can comprise contacting, inany order, (a) an activator-support, (b) a mixture comprisingcyclohexene and a metallocene compound, and (c) an organoaluminumcompound, to produce the catalyst composition. In a further embodiment,the mixture can comprise cyclohexene, 1-hexene, and the metallocenecompound. In another embodiment, a process for producing a catalystcomposition is provided, and in this embodiment, the process cancomprise (i) contacting an activator-support and an organoaluminumcompound for a first period of time to form a precontacted mixture, and(ii) contacting the precontacted mixture with a second mixturecomprising cyclohexene and a metallocene compound for a second period oftime to form the catalyst composition. In a further embodiment, thesecond mixture can comprise cyclohexene, 1-hexene, and the metallocenecompound. While not wishing to be bound by the following theory, it isbelieved that the metallocene-based catalyst compositions, prepared asdescribed herein, may have unexpected increases in catalyst activity, orimproved solubility of the metallocene compound, or both. Moreover,polymers produced using the metallocene-based catalyst compositions,prepared as described herein, may have lower levels of residualsolvents.

Catalyst compositions also are encompassed by the present invention. Inone embodiment, the catalyst composition can comprise (A) anactivator-support, (B) an organoaluminum compound, (C) a metallocenecompound, and (D) cyclohexene (and optionally, 1-hexene). In anotherembodiment, the catalyst composition can comprise (I) a precontactedmixture comprising an activator-support and an organoaluminum compound,(II) a metallocene compound, and (III) cyclohexene (and optionally,1-hexene).

The present invention also contemplates and encompasses olefinpolymerization processes. Such processes can comprise contacting acatalyst composition with an olefin monomer and optionally an olefincomonomer in a polymerization reactor system under polymerizationconditions to produce an olefin polymer. Generally, the catalystcomposition employed can comprise any of the metallocene-based catalystsystems disclosed herein, for instance, any of the metallocenecompounds, any of activator-supports, and any of the organoaluminumcompounds disclosed herein.

Polymers produced from the polymerization of olefins, resulting inhomopolymers, copolymers, or terpolymers, can be used to produce variousarticles of manufacture.

Both the foregoing summary and the following detailed descriptionprovide examples and are explanatory only. Accordingly, the foregoingsummary and the following detailed description should not be consideredto be restrictive. Further, features or variations may be provided inaddition to those set forth herein. For example, certain aspects andembodiments may be directed to various feature combinations andsub-combinations described in the detailed description.

DEFINITIONS

To define more clearly the terms used herein, the following definitionsare provided. Unless otherwise indicated, the following definitions areapplicable to this disclosure. If a term is used in this disclosure butis not specifically defined herein, the definition from the IUPACCompendium of Chemical Terminology, 2^(nd) Ed (1997), can be applied, aslong as that definition does not conflict with any other disclosure ordefinition applied herein, or render indefinite or non-enabled any claimto which that definition is applied. To the extent that any definitionor usage provided by any document incorporated herein by referenceconflicts with the definition or usage provided herein, the definitionor usage provided herein controls.

While compositions and methods are often described in terms of“comprising” various components or steps, the compositions and methodscan also “consist essentially of” or “consist of” the various componentsor steps, unless stated otherwise.

The terms “a,” “an,” and “the” are intended to include pluralalternatives, e.g., at least one. For instance, the disclosure of “anactivator-support” and “a metallocene compound” is meant to encompassone, or mixtures or combinations of more than one, activator-support andmetallocene compound, respectively, unless otherwise specified.

For any particular compound or group disclosed herein, any name orstructure (general or specific) presented is intended to encompass allconformational isomers, regioisomers, stereoisomers, and mixturesthereof that can arise from a particular set of substituents, unlessotherwise specified. The name or structure (general or specific) alsoencompasses all enantiomers, diastereomers, and other optical isomers(if there are any) whether in enantiomeric or racemic forms, as well asmixtures of stereoisomers, as would be recognized by a skilled artisan,unless otherwise specified. A general reference to pentane, for example,includes n-pentane, 2-methyl-butane, and 2,2-dimethylpropane; and ageneral reference to a butyl group includes a n-butyl group, a sec-butylgroup, an iso-butyl group, and a t-butyl group.

Also, unless otherwise specified, any carbon-containing group orcompound for which the number of carbon atoms is not specified can have1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20carbon atoms, or any range or combination of ranges between thesevalues. For example, unless otherwise specified, any carbon-containinggroup or compound can have from 1 to 20 carbon atoms, from 1 to 18carbon atoms, from 1 to 12 carbon atoms, from 1 to 8 carbon atoms, from2 to 20 carbon atoms, from 2 to 12 carbon atoms, from 2 to 8 carbonatoms, or from 2 to 6 carbon atoms, and the like. Moreover, otheridentifiers or qualifying terms can be utilized to indicate the presenceof, or absence of, a particular substituent, a particularregiochemistry, and/or stereochemistry, or the presence or absence of abranched underlying structure or backbone. Any specificcarbon-containing group is limited according to the chemical andstructural requirements for that specific group, as understood by one ofordinary skill in the art.

Other numerical ranges are disclosed herein. When a range of any type isdisclosed or claimed herein, the intent is to disclose or claimindividually each possible number that such a range could reasonablyencompass, including end points of the range as well as any sub-rangesand combinations of sub-ranges encompassed therein, unless otherwisespecified. As a representative example, the present disclosure setsforth that a weight ratio of a first metallocene compound to a secondmetallocene compound can be in a range from about 1:10 to about 10:1 incertain embodiments. By a disclosure that the weight ratio can be in arange from about 1:10 to about 10:1, the intent is to recite that theweight ratio can be any weight ratio within the range and, for example,can be equal to about 1:10, about 1:9, about 1:8, about 1:7, about 1:6,about 1:5, about 1:4, about 1:3, about 1:2, about 1:1, about 2:1, about3:1, about 4:1, about 5:1, about 6:1, about 7:1, about 8:1, about 9:1,or about 10:1. Additionally, the weight ratio can be within any rangefrom about 1:10 to about 10:1 (for example, the weight ratio can be in arange from about 1:2 to about 2:1), and this also includes anycombination of ranges between about 1:10 and 10:1. Likewise, all otherranges disclosed herein should be interpreted in a manner similar tothese examples.

The term “polymer” is used herein generically to include olefinhomopolymers, copolymers, terpolymers, and so forth. A copolymer can bederived from an olefin monomer and one olefin comonomer, while aterpolymer can be derived from an olefin monomer and two olefincomonomers. Accordingly, “polymer” encompasses copolymers andterpolymers derived from any olefin monomer and comonomer(s) disclosedherein. Similarly, an ethylene polymer would include ethylenehomopolymers, ethylene copolymers, ethylene terpolymers, and the like.As an example, an olefin copolymer, such as an ethylene copolymer, canbe derived from ethylene and a comonomer, such as 1-butene, 1-hexene, or1-octene. If the monomer and comonomer were ethylene and 1-hexene,respectively, the resulting polymer can be categorized an asethylene/1-hexene copolymer. The term “polymer” also is meant to includeall molecular weight polymers, and is inclusive of lower molecularweight polymers or oligomers. The term “polymer” as used herein isintended to encompass oligomers derived from any olefin monomerdisclosed herein (as well from an olefin monomer and one olefincomonomer, an olefin monomer and two olefin comonomers, and so forth).

In like manner, the scope of the term “polymerization” includeshomopolymerization, copolymerization, and terpolymerization, as well asprocesses that might also be referred to as oligomerization processes.Therefore, a copolymerization process can involve contacting an olefinmonomer (e.g., ethylene) and an olefin comonomer (e.g., 1-hexene) toproduce an olefin copolymer.

The terms “catalyst composition,” “catalyst mixture,” “catalyst system,”and the like, do not depend upon the actual product or compositionresulting from the contact or reaction of the initial components of thedisclosed or claimed catalyst composition/mixture/system, the nature ofthe active catalytic site, or the fate of the organoaluminum compound,the metallocene compound, or the activator-support, after combiningthese components. Therefore, the terms “catalyst composition,” “catalystmixture,” “catalyst system,” and the like, can encompass the initialstarting components of the composition, as well as whatever product(s)may result from contacting these initial starting components, and thisis inclusive of both heterogeneous and homogenous catalyst systems orcompositions. The terms “catalyst composition,” “catalyst mixture,”“catalyst system,” and the like, may be used interchangeably throughoutthis disclosure.

The terms “contact product,” “contacting,” and the like, are used hereinto describe methods and compositions wherein the components are combinedor contacted together in any order, in any manner, and for any length oftime, unless otherwise specified. For example, the components can becontacted by blending or mixing. Further, unless otherwise specified,the contacting of any component can occur in the presence or absence ofany other component of the methods and compositions described herein.Combining additional materials or components can be done by any suitablemethod. These terms encompass mixtures, blends, solutions, slurries,reaction products, and the like, as well as combinations thereof.

A “precontacted mixture” describes a mixture of catalyst components thatare combined or contacted for a period of time prior to being contactedwith other catalyst components. According to this description, it ispossible for the components of the precontacted mixture, once contacted,to have reacted to form at least one chemical compound, formulation,species, or structure different from the distinct initial compounds orcomponents used to prepare the precontacted mixture.

Although any methods and materials similar or equivalent to thosedescribed herein can be used in the practice or testing of theinvention, the typical methods and materials are herein described.

All publications and patents mentioned herein are incorporated herein byreference for the purpose of describing and disclosing, for example, theconstructs and methodologies that are described in the publications,which might be used in connection with the presently describedinvention.

DETAILED DESCRIPTION OF THE INVENTION

Disclosed herein are methods for preparing metallocene-based catalystcompositions using cyclohexene, 1-hexene, or mixtures of cyclohexene and1-hexene. Polymerization processes utilizing these catalyst compositionsalso are disclosed. A potential benefit of the methods and catalystcompositions disclosed herein, which utilize cyclohexene alone or incombination with 1-hexene instead of toluene alone or in combinationwith 1-hexene, is an unexpected increase in catalyst activity. Anotherpotential and unexpected benefit is improved solubility and lessprecipitation of the metallocene compound. Yet another potential andunexpected benefit is the lower level of residual solvents present inpolymers produced using the catalyst compositions and polymerizationprocesses disclosed herein. Additionally, the reduction and/orelimination of residual toluene in the produced polymer is anotherpotential benefit, since recent regulations indicate that toluene canhave a number of hazards associated with its use. Other potentialbenefits of the compositions and methods disclosed herein are readilyapparent to those of skill in the art.

Methods for Preparing Catalyst Compositions

Various processes for preparing a catalyst composition containing ametallocene compound, an activator-support, and an organoaluminumcompound are disclosed and described. One or more than one metallocenecompound, activator-support, and organoaluminum compound can be employedin the disclosed processes and compositions. A process for producing acatalyst composition consistent with embodiments of this invention cancomprise (or consist essentially of, or consist of):

(i) contacting an activator-support and an organoaluminum compound for afirst period of time to form a precontacted mixture (alternatively, andequivalently, a first mixture); and

(ii) contacting the precontacted mixture with a second mixturecomprising cyclohexene and a metallocene compound for a second period oftime to form the catalyst composition.

Generally, the features of any of the processes disclosed herein (e.g.,the activator-support, the organoaluminum compound, the metallocenecompound, the first period of time, the second period of time, amongothers) are independently described herein, and these features can becombined in any combination to further describe the disclosed processes.Moreover, other process steps can be conducted before, during, and/orafter any of the steps listed in the disclosed processes, unless statedotherwise. Additionally, catalyst compositions produced in accordancewith the disclosed processes are within the scope of this disclosure andare encompassed herein.

In some embodiments, the second mixture can comprise cyclohexene,1-hexene, and the metallocene compound. Typically, in these embodiments,the weight ratio (wt. %:wt. %) of 1-hexene to cyclohexene(1-hexene:cyclohexene) in the second mixture can fall within a rangefrom about 99:1 to about 1:99, from about 95:5 to about 10:90, fromabout 90:10 to about 20:80, from about 90:10 to about 50:50, from about90:10 to about 60:40, from about 85:15 to about 25:75, from about 85:15to about 60:40, or from about 85:15 to about 70:30, and the like. Otherappropriate ranges for the weight ratio of 1-hexene:cyclohexene in thesecond mixture are readily apparent from this disclosure.

Step (i) of the process often can be referred to as the precontactingstep, and in the precontacting step, an activator-support can becombined with an organoaluminum compound for a first period of time toform a precontacted mixture. The precontacting step can be conducted ata variety of temperatures and time periods. For instance, theprecontacting step can be conducted at a precontacting temperature in arange from about 0° C. to about 100° C.; alternatively, from about 0° C.to about 75° C.; alternatively, from about 10° C. to about 75° C.;alternatively, from about 20° C. to about 60° C.; alternatively, fromabout 20° C. to about 50° C.; alternatively, from about 15° C. to about45° C.; or alternatively, from about 20° C. to about 40° C. In these andother embodiments, these temperature ranges also are meant to encompasscircumstances where the precontacting step is conducted at a series ofdifferent temperatures, instead of at a single fixed temperature,falling within the respective ranges.

The duration of the precontacting step (the first period of time) is notlimited to any particular period of time. Hence, the first period oftime can be, for example, in a time period ranging from as little as1-10 seconds to as long as 48 hours, or more. The appropriate firstperiod of time can depend upon, for example, the precontactingtemperature, the amounts of the activator-support and the organoaluminumcompound in the precontacted mixture, the presence of diluents orsolvents in the precontacting step, and the degree of mixing, amongother variables. Generally, however, the first period of time can be atleast about 5 sec, at least about 10 sec, at least about 30 sec, atleast about 1 min, at least about 5 min, at least about 10 min, and soforth. Typical ranges for the first period of time can include, but arenot limited to, from about 1 sec to about 48 hr, from about 10 sec toabout 48 hr, from about 30 sec to about 24 hr, from about 30 sec toabout 6 hr, from about 1 min to about 12 hr, from about 5 min to about24 hr, or from about 10 min to about 8 hr, as well as ranges withinthese exemplary ranges.

Often, the precontacting step can be conducted by combining a slurry ofthe activator-support in a first diluent with a solution of theorganoaluminum compound in the same or a different diluent, and mixingto ensure sufficient contacting of the activator-support and theorganoaluminum compound. However, any suitable procedure known to thoseof skill in the art for thoroughly combining the activator-support andthe organoaluminum compound can be employed. Non-limiting examples ofsuitable hydrocarbon diluents can include, but are not limited to,propane, isobutane, n-butane, n-pentane, isopentane, neopentane,n-hexane, heptane, octane, cyclohexane, cycloheptane, methylcyclohexane,methylcycloheptane, benzene, toluene, xylene, ethylbenzene, and thelike, or combinations thereof. In some embodiments, the first diluentcan comprise cyclohexene or 1-hexene, or a mixture of cyclohexene and1-hexene. In another embodiment, the activator-support can be present asa dry solid, and the precontacting step can be conducted by combiningthe dry activator-support with a solution of the organoaluminum compoundin a first diluent (e.g., a suitable hydrocarbon solvent, such ascyclohexane, isobutane, n-butane, n-pentane, isopentane, neopentane,hexane, heptane, and the like, as well as combinations thereof), andmixing to ensure sufficient contacting of the activator-support and theorganoaluminum compound. Accordingly, any suitable procedure known tothose of skill in the art for contacting or combining theactivator-support and the organoaluminum compound can be employed.

In step (ii) of the process, the precontacted mixture (often, a slurry)can be contacted with the second mixture containing one or moremetallocene compounds and cyclohexene (and 1-hexene, if used) to formthe catalyst composition. Step (ii), likewise, can be conducted at avariety of temperatures and time periods. For instance, step (ii) can beconducted at a temperature in a range from about 0° C. to about 100° C.;alternatively, from about 10° C. to about 75° C.; alternatively, fromabout 20° C. to about 60° C.; alternatively, from about 15° C. to about45° C.; or alternatively, from about 20° C. to about 40° C. In these andother embodiments, these temperature ranges are also meant to encompasscircumstances where step (ii) is conducted at a series of differenttemperatures, instead of at a single fixed temperature, falling withinthe respective ranges. As an example, the precontacted mixture and thesecond mixture can be contacted at an elevated temperature, following bycooling to a lower temperature for longer term storage of the finishedcatalyst composition.

The second period of time is not limited to any particular period oftime. Hence, the second period of time can range from as little as 1-10seconds to as long as 48 hours, or more. The appropriate second periodof time can depend upon, for example, the temperature, the amounts ofthe precontacted mixture and the second mixture, the presence ofdiluents or solvents in step (ii), the degree of mixing, andconsiderations for long term storage, among other variables. Generally,however, the second period of time can be at least about 5 sec, at leastabout 10 sec, at least about 30 sec, at least about 1 min, at leastabout 5 min, at least about 10 min, and so forth. Assuming the catalystcomposition is not intended for long term storage, which could extendfor days or weeks, typical ranges for the second period of time caninclude, but are not limited to, from about 1 sec to about 48 hr, fromabout 10 sec to about 48 hr, from about 30 sec to about 24 hr, fromabout 30 sec to about 6 hr, from about 1 min to about 6 hr, from about 5min to about 24 hr, or from about 10 min to about 8 hr.

Often, step (ii) can be conducted by combining the precontacted mixture(e.g., a slurry) with the second mixture comprising the metallocenecompound and cyclohexene (and 1-hexene, if used), and mixing to ensuresufficient contacting to form the finished catalyst composition. In oneembodiment, the second mixture comprising the metallocene compound andcyclohexene (and 1-hexene, if used) is a slurry, i.e., the metallocenecompound is not dissolved at standard temperature (25° C.) and pressure(1 atm). In another embodiment, and more typically, the mixturecomprising the metallocene compound and cyclohexene (and 1-hexene, ifused) is a solution, i.e., the metallocene compound is substantiallydissolved at standard temperature and pressure. In this embodiment,there is no visual precipitation of solid metallocene compound from thesolution. Moreover, when the solution is filtered, the absorbance of thesolution of the metallocene compound (when tested at a wavelength in theUV-visible spectrum of peak absorbance for the metallocene compound)often does not change by more than 5% from the unfiltered solution.

In another embodiment, an additional amount of an organoaluminumcompound can be combined with the precontacted mixture and the secondmixture, and this organoaluminum compound can be the same as ordifferent from the organoaluminum compound utilized in the precontactingstep. As described herein, the organoaluminum compound can be present asa solution in any suitable hydrocarbon solvent, non-limiting examples ofwhich can include cyclohexane, isobutane, n-butane, n-pentane,isopentane, neopentane, hexane, heptane, and the like, as well ascombinations thereof.

In a related embodiment, a catalyst composition consistent with thisinvention can comprise (I) a precontacted mixture comprising anactivator-support and an organoaluminum compound, (II) a metallocenecompound, and (III) cyclohexene.

In another related embodiment, a catalyst composition consistent withthis invention can comprise (I) a precontacted mixture comprising anactivator-support and an organoaluminum compound, (II) a metallocenecompound, (III) cyclohexene, and (IV) 1-hexene. The weight ratio of1-hexene:cyclohexene is not particularly limited, but often falls withina range from about 90:10 to about 20:80, from about 90:10 to about50:50, or from about 85:15 to about 60:40.

Unexpectedly, these catalyst compositions and methods of theirpreparation can result in improvements in catalyst activity. Forinstance, the activity of the catalyst composition can be greater (e.g.,by at least about 1%, by at least about 2%, by at least about 10%, by atleast about 25%, from about 1% to about 100%, from about 2% to about50%, or from about 5% to about 50%) than that of a catalyst systemobtained by using toluene (or toluene and 1-hexene) instead ofcyclohexene in the second mixture, under the same catalyst preparationand polymerization conditions. The same polymerization conditions referto slurry polymerization conditions, using isobutane as a diluent, andwith a polymerization temperature of 90° C. and a reactor pressure of420 psig. Moreover, all components used to prepare the catalyst systemsare held constant (e.g., same amount/type of metallocene compound, sameamount/type of organoaluminum, same amount/type of activator-support,such as fluorided silica-coated alumina or sulfated alumina) and allpolymerization conditions are held constant (e.g., same polymerizationtemperature and same polymerization pressure). Hence, the onlydifference is the method used to produce the catalyst system, i.e., theuse of cyclohexene as a diluent or solvent for the metallocene componentinstead of toluene (and 1-hexene, if used).

In another embodiment, and unexpectedly, the activity of the catalystcomposition can be greater (e.g., by at least about 1%, by at leastabout 2%, by at least about 10%, by at least about 25%, from about 1% toabout 100%, from about 2% to about 50%, or from about 5% to about 50%)than that of a catalyst system obtained by using toluene and 1-hexene(or toluene) instead of cyclohexene and 1-hexene in the second mixture,under the same catalyst preparation and polymerization conditions. Asabove, the same polymerization conditions refer to slurry polymerizationconditions, using isobutane as a diluent, and with a polymerizationtemperature of 90° C. and a reactor pressure of 420 psig. Moreover, allcomponents used to prepare the catalyst systems are held constant (e.g.,same amount/type of metallocene compound, same amount/type oforganoaluminum, same amount/type of activator-support, such as fluoridedsilica-coated alumina or sulfated alumina) and all polymerizationconditions are held constant (e.g., same polymerization temperature,same pressure). Hence, the only difference is the method used to producethe catalyst system, i.e., the use of cyclohexene and 1-hexene as adiluent or solvent for the metallocene component instead of toluene and1-hexene (or toluene).

In another embodiment, and unexpectedly, the activity of the catalystcomposition can be greater (e.g., by at least about 1%, by at leastabout 2%, by at least about 10%, by at least about 25%, from about 1% toabout 100%, from about 2% to about 50%, or from about 5% to about 50%)than that of a catalyst system obtained by first combining theactivator-support and the second mixture, and then combining theorganoaluminum compound, under the same polymerization conditions.Again, this comparison is under the same polymerization conditions, suchthat the only difference is the order or sequence of contacting therespective catalyst components (precontacting the activator-support andthe organoaluminum compound versus no precontacting).

In another embodiment, and unexpectedly, the second mixture comprisingcyclohexene, 1-hexene, and the metallocene compound has lessprecipitation of the metallocene compound and/or the metallocenecompound precipitates at a lower temperature than that of a mixturecontaining toluene, 1-hexene, and the metallocene compound, whencompared at the same metallocene loading. For instance, in someembodiments, there is substantially no precipitation of the mixturecomprising cyclohexene, 1-hexene, and the metallocene compound at 0° C.In these instances, there is no visual precipitation of solidmetallocene compound from the solution. Moreover, when the solution isfiltered, the absorbance of the solution of the metallocene compound(when tested at a wavelength in the UV-visible spectrum of peakabsorbance for the metallocene compound) often does not change by morethan 5% from the unfiltered solution. Metallocene solutions incyclohexene or mixtures with 1-hexene, which can withstand lowertemperatures than comparable solutions in toluene alone or mixtures oftoluene and 1-hexene, can be beneficial due to the reduced risk ofmetallocene precipitation during transportation and/or storage.

In other embodiments of this invention, a process for preparing acatalyst composition containing a metallocene compound, anactivator-support, and an organoaluminum compound can comprise (orconsist essentially of, or consist of) contacting, in any order:

-   -   (a) an activator-support;    -   (b) a mixture comprising cyclohexene and a metallocene compound;        and    -   (c) an organoaluminum compound;        to produce the catalyst composition.

Generally, the features of this process (e.g., the activator-support,the organoaluminum compound, the metallocene compound, the order ofcontacting, among others) are independently described herein, and thesefeatures can be combined in any combination to further describe thedisclosed processes. Moreover, other process steps can be conductedbefore, during, and/or after any of the steps listed in the disclosedprocesses, unless stated otherwise. Additionally, catalyst compositionsproduced in accordance with this process are within the scope of thisdisclosure and are encompassed herein.

In some embodiments, the metallocene mixture can comprise cyclohexene,1-hexene, and the metallocene compound. Typically, the weight ratio of1-hexene to cyclohexene (1-hexene:cyclohexene) in the mixture can fallwithin a range from about 99:1 to about 1:99, from about 95:5 to about10:90, from about 90:10 to about 20:80, from about 90:10 to about 50:50,from about 90:10 to about 60:40, from about 85:15 to about 25:75, fromabout 85:15 to about 60:40, or from about 85:15 to about 70:30, and thelike. Other appropriate ranges for the weight ratio of1-hexene:cyclohexene in the mixture are readily apparent from thisdisclosure.

In this process, the activator-support, the mixture containing themetallocene compound and cyclohexene (and 1-hexene, if used), and theorganoaluminum compound can be contacted or combined in any order, andunder any suitable conditions, to form the catalyst composition. Thus, avariety of temperatures and time periods can be employed. For instance,the catalyst components can be contacted a temperature in a range fromabout 0° C. to about 100° C.; alternatively, from about 0° C. to about75° C.; alternatively, from about 10° C. to about 75° C.; alternatively,from about 20° C. to about 60° C.; alternatively, from about 20° C. toabout 50° C.; alternatively, from about 15° C. to about 45° C.; oralternatively, from about 20° C. to about 40° C. In these and otherembodiments, these temperature ranges also are meant to encompasscircumstances where the components are contacted at a series ofdifferent temperatures, instead of at a single fixed temperature,falling within the respective ranges. As an example, the initialcontacting of the components of the catalyst system can be conducted atan elevated temperature, following by cooling to a lower temperature forlonger term storage of the finished catalyst composition.

The duration of the contacting of the components to form the catalystcomposition is not limited to any particular period of time. Hence, thisperiod of time can be, for example, from as little as 1-10 seconds to aslong as 24-48 hours, or more. The appropriate period of time can dependupon, for example, the contacting temperature, the respective amounts ofthe activator-support, metallocene compound, and organoaluminum compoundto be contacted or combined, the amount of cyclohexene (and 1-hexene, ifused), the degree of mixing, and considerations for long term storage,among other variables. Generally, however, the period of time forcontacting can be at least about 5 sec, at least about 10 sec, at leastabout 30 sec, at least about 1 min, at least about 5 min, at least about10 min, and so forth. Assuming the catalyst composition is not intendedfor long term storage, which could extend for days or weeks, typicalranges for the contacting time can include, but are not limited to, fromabout 1 sec to about 48 hr, from about 10 sec to about 48 hr, from about30 sec to about 24 hr, from about 30 sec to about 6 hr, from about 1 minto about 6 hr, from about 5 min to about 24 hr, or from about 10 min toabout 8 hr.

Often, the activator-support can be present as a slurry. Accordingly,the activator-support can be present as a slurry of theactivator-support in a first diluent. The first diluent can comprise anysuitable hydrocarbon, illustrative and non-limiting examples of whichcan include propane, cyclohexane, isobutane, n-butane, n-pentane,isopentane, neopentane, n-hexane, and the like, or combinations thereof.In some embodiments, the first diluent can comprise cyclohexene or1-hexene, or a mixture of cyclohexene and 1-hexene. Often, theorganoaluminum compound also can be present as a solution in anysuitable hydrocarbon solvent, and the solvent can be the same as ordifferent from the hydrocarbon present in the slurry of theactivator-support. In other embodiments, the activator-support can bepresent as a dry solid.

In one embodiment, the catalyst composition can be prepared by firstcontacting the organoaluminum compound and the activator-support, andthen combining the mixture containing the metallocene compound andcyclohexene (and 1-hexene, if used), and mixing to ensure sufficientcontacting of all components. In another embodiment, the catalystcomposition can be prepared by first contacting the organoaluminumcompound and the mixture containing the metallocene compound andcyclohexene (and 1-hexene, if used), and then combining theactivator-support, and mixing to ensure sufficient contacting of allcomponents. In yet another embodiment, the catalyst composition can beprepared by combining the organoaluminum compound, theactivator-support, and the mixture containing the metallocene compoundand cyclohexene (and 1-hexene, if used) substantially contemporaneously,and mixing to ensure sufficient contacting of all components. For eachof these orders of addition, the activator-support can be present as aslurry in a first diluent or, alternatively, the activator-support canbe present as a dry solid. Likewise, the metallocene compound can bepresent in the mixture with cyclohexene or, alternatively, themetallocene compound can be present in the mixture with cyclohexene and1-hexene. In these and other embodiments, the organoaluminum compoundcan be present as a solution in a suitable hydrocarbon solvent.

In one embodiment, the mixture comprising the metallocene compound andcyclohexene (and 1-hexene, if used) is a slurry, i.e., the metallocenecompound is not dissolved at standard temperature (25° C.) and pressure(1 atm). In another embodiment, and more typically, the mixturecomprising the metallocene compound and cyclohexene (and 1-hexene, ifused) is a solution, i.e., the metallocene compound is substantiallydissolved at standard temperature and pressure. In this embodiment,there is no visual precipitation of solid metallocene compound from thesolution. Moreover, when the solution is filtered, the absorbance of thesolution of the metallocene compound (when tested at a wavelength in theUV-visible spectrum of peak absorbance for the metallocene compound)often does not change by more than 5% from the unfiltered solution.

In a related embodiment, a catalyst composition consistent with thisinvention can comprise (A) an activator-support, (B) an organoaluminumcompound, (C) a metallocene compound, and (D) cyclohexene.

In another related embodiment, a catalyst composition consistent withthis invention can comprise (A) an activator-support, (B) anorganoaluminum compound, (C) a metallocene compound, (D) cyclohexene,and (E) 1-hexene. The weight ratio of 1-hexene:cyclohexene is notparticularly limited, but often falls within a range from about 90:10 toabout 20:80, from about 90:10 to about 50:50, or from about 85:15 toabout 60:40.

Unexpectedly, these catalyst compositions and methods of theirpreparation can result in improvements in catalyst activity. Forinstance, the activity of the catalyst composition can be greater (e.g.,by at least about 1%, by at least about 2%, by at least about 10%, by atleast about 25%, from about 1% to about 100%, from about 2% to about50%, or from about 5% to about 50%) than that of a catalyst systemobtained by using toluene (or toluene and 1-hexene) instead ofcyclohexene in the mixture, under the same catalyst preparation andpolymerization conditions. The same polymerization conditions refer toslurry polymerization conditions, using isobutane as a diluent, and witha polymerization temperature of 90° C. and a reactor pressure of 420psig. Moreover, all components used to prepare the catalyst systems areheld constant (e.g., same amount/type of metallocene compound, sameamount/type of organoaluminum, same amount/type of activator-support,such as fluorided silica-coated alumina or sulfated alumina) and allpolymerization conditions are held constant (e.g., same polymerizationtemperature, same pressure). Hence, the only difference is the methodused to produce the catalyst system, i.e., the use of cyclohexene as adiluent or solvent for the metallocene component instead of toluene (and1-hexene, if used).

In another embodiment, and unexpectedly, the activity of the catalystcomposition can be greater (e.g., by at least about 1%, by at leastabout 2%, by at least about 10%, by at least about 25%, from about 1% toabout 100%, from about 2% to about 50%, or from about 5% to about 50%)than that of a catalyst system obtained by using toluene and 1-hexene(or toluene) instead of cyclohexene and 1-hexene in the mixture, underthe same catalyst preparation and polymerization conditions. As above,the same polymerization conditions refer to slurry polymerizationconditions, using isobutane as a diluent, and with a polymerizationtemperature of 90° C. and a reactor pressure of 420 psig. Moreover, allcomponents used to prepare the catalyst systems are held constant (e.g.,same amount/type of metallocene compound, same amount/type oforganoaluminum, same amount/type of activator-support, such as fluoridedsilica-coated alumina or sulfated alumina) and all polymerizationconditions are held constant (e.g., same polymerization temperature andsame polymerization pressure). Hence, the only difference is the methodused to produce the catalyst system, i.e., the use of cyclohexene and1-hexene as a diluent or solvent for the metallocene component insteadof toluene and 1-hexene (or toluene).

In another embodiment, and unexpectedly, the mixture comprisingcyclohexene, 1-hexene, and the metallocene compound has lessprecipitation of the metallocene compound and/or the metallocenecompound precipitates at a lower temperature than that of a mixturecontaining toluene, 1-hexene, and the metallocene compound, whencompared at the same metallocene loading. For instance, in someembodiments, there is substantially no precipitation of the mixturecomprising cyclohexene, 1-hexene, and the metallocene compound at 0° C.In these instances, there is no visual precipitation of solidmetallocene compound from the solution. Moreover, when the solution isfiltered, the absorbance of the solution of the metallocene compound(when tested at a wavelength in the UV-visible spectrum of peakabsorbance for the metallocene compound) often does not change by morethan 5% from the unfiltered solution.

Consistent with certain embodiments of this invention, the catalystcomposition and the method of preparing the catalyst composition cancomprise more than one metallocene compound, for example, one bridgedmetallocene compound and one unbridged metallocene compound, or two ormore bridged metallocene compounds, or two or more unbridged metallocenecompounds. In such instances, the weight ratio (wt. %:wt. %) of thefirst metallocene compound to the second metallocene compound generallycan be in a range of from about 1:100 to about 100:1, from about 1:50 toabout 50:1, from about 1:25 to about 25:1, from about 1:10 to about10:1, or from about 1:5 to about 5:1. Accordingly, suitable ranges forthe weight ratio of the first metallocene compound to the secondmetallocene compound can include, but are not limited to, from about1:15 to about 15:1, from about 1:10 to about 10:1, from about 1:8 toabout 8:1, from about 1:5 to about 5:1, from about 1:4 to about 4:1,from about 1:3 to about 3:1, from about 1:2 to about 2:1, from about1:1.8 to about 1.8:1, from about 1:1.5 to about 1.5:1, from about 1:1.3to about 1.3:1, from about 1:1.25 to about 1.25:1, from about 1:1.2 toabout 1.2:1, from about 1:1.15 to about 1.15:1, from about 1:1.1 toabout 1.1:1, or from about 1:1.05 to about 1.05:1, and the like.

Generally, in the catalyst compositions and methods of their preparationdisclosed herein, the weight ratio (wt. %:wt. %) of activator-support(s)to organoaluminum compound(s) can be in a range from about 1:10 to about1000:1, or from about 1:5 to about 1000:1. If more than oneorganoaluminum compound and/or more than one activator-support areemployed, this ratio is based on the total weight of each respectivecomponent. In an embodiment, the weight ratio of the activator-supportto the organoaluminum compound can be in a range from about 1:1 to about500:1, from about 1:3 to about 200:1, or from about 1:1 to about 100:1.

Likewise, the weight ratio (wt. %:wt. %) of metallocene compound(s) toactivator-support(s) can be in a range from about 1:1 to about1:1,000,000, or from about 1:5 to about 1:250,000. If more than onemetallocene compound and/or more than one activator-support areemployed, this ratio is based on the total weight of each respectivecomponent. In an embodiment, the weight ratio of metallocene compound toactivator-support can be in a range from about 1:10 to about 1:10,000,or from about 1:20 to about 1:1000.

In some embodiments, the catalyst compositions and methods of theirpreparation are substantially free of aluminoxane compounds, organoboronor organoborate compounds, ionizing ionic compounds, and/or othersimilar materials; alternatively, substantially free of aluminoxanes;alternatively, substantially free or organoboron or organoboratecompounds; or alternatively, substantially free of ionizing ioniccompounds. In these embodiments, the catalyst composition has catalystactivity, as discussed herein, in the absence of these additionalmaterials. For example, a catalyst composition of the present inventioncan consist essentially of a metallocene compound, an activator-support,an organoaluminum compound, and cyclohexene (or consist essentially of ametallocene compound, an activator-support, an organoaluminum compound,cyclohexene, and 1-hexene), wherein no other materials are present inthe catalyst composition which would increase/decrease the activity ofthe catalyst composition by more than about 10% from the catalystactivity of the catalyst composition in the absence of said materials.

Metallocene Compounds

Metallocene-based catalyst compositions consistent with this inventioncan contain a bridged metallocene compound and/or an unbridgedmetallocene compound. Metallocene-based catalyst compositions consistentwith this invention can also contain two or more bridged metallocenecompounds and/or two or more unbridged metallocene compounds. Themetallocene compound can comprise, for example, a transition metal (oneor more than one) from Groups IIIB-VIIIB of the Periodic Table of theElements. In one embodiment, the metallocene compound can comprise aGroup III, IV, V, or VI transition metal, or a combination of two ormore transition metals. The metallocene compound can comprise chromium,titanium, zirconium, hafnium, vanadium, or a combination thereof, or cancomprise titanium, zirconium, hafnium, or a combination thereof, inother embodiments. In further embodiments, the metallocene compound cancomprise titanium, or zirconium, or hafnium, either singly or incombination.

In some embodiments of this invention, the metallocene compound cancomprise a bridged metallocene compound, e.g., with titanium, zirconium,or hafnium, such as a bridged zirconium or hafnium based metallocenecompound with a fluorenyl group, and with no aryl groups on the bridginggroup, or a bridged zirconium or hafnium based metallocene compound witha cyclopentadienyl group and a fluorenyl group, and with no aryl groupson the bridging group. Such bridged metallocenes, in some embodiments,can contain an alkenyl substituent (e.g., a terminal alkenyl) on thebridging group and/or on a cyclopentadienyl-type group (e.g., acyclopentadienyl group or a fluorenyl group). In another embodiment, themetallocene compound can comprise a bridged zirconium or hafnium basedmetallocene compound with a fluorenyl group, and an aryl group on thebridging group; alternatively, a bridged zirconium or hafnium basedmetallocene compound with a cyclopentadienyl group and fluorenyl group,and an aryl group on the bridging group; alternatively, a bridgedzirconium based metallocene compound with a fluorenyl group, and an arylgroup on the bridging group; or alternatively, a bridged hafnium basedmetallocene compound with a fluorenyl group, and an aryl group on thebridging group. In these and other embodiments, the aryl group on thebridging group can be a phenyl group. Optionally, these bridgedmetallocenes can contain an alkenyl substituent (e.g., a terminalalkenyl) on the bridging group and/or on a cyclopentadienyl-type group.

In some embodiments, the metallocene compound can comprise a bridgedzirconium or hafnium based metallocene compound with two indenyl groups(e.g., a bis-indenyl metallocene compound). Hence, the metallocenecompound can comprise a bridged zirconium based metallocene compoundwith two indenyl groups, or alternatively, a bridged hafnium basedmetallocene compound with two indenyl groups. In some embodiments, anaryl group can be present on the bridging group, while in otherembodiments, there are no aryl groups present on the bridging group.Optionally, these bridged indenyl metallocenes can contain an alkenylsubstituent (e.g., a terminal alkenyl) on the bridging group and/or onthe indenyl group (one or both indenyl groups). The bridging atom of thebridging group can be, for instance, a carbon atom or a silicon atom;alternatively, the bridge can contain a chain of two carbon atoms, achain of two silicon atoms, and so forth.

Illustrative and non-limiting examples of bridged metallocene compounds(e.g., with zirconium or hafnium) that can be employed in catalystsystems consistent with embodiments of the present invention aredescribed in U.S. Pat. Nos. 7,026,494, 7,041,617, 7,226,886, 7,312,283,7,517,939, and 7,619,047, the disclosures of which are incorporatedherein by reference in their entirety.

In some embodiments of this invention, the metallocene compound cancomprise an unbridged metallocene; alternatively, an unbridged zirconiumor hafnium based metallocene compound and/or an unbridged zirconiumand/or hafnium based dinuclear metallocene compound; alternatively, anunbridged zirconium or hafnium based metallocene compound containing twocyclopentadienyl groups, two indenyl groups, or a cyclopentadienyl andan indenyl group; alternatively, an unbridged zirconium basedmetallocene compound containing two cyclopentadienyl groups, two indenylgroups, or a cyclopentadienyl and an indenyl group. Illustrative andnon-limiting examples of unbridged metallocene compounds (e.g., withzirconium or hafnium) that can be employed in catalyst systemsconsistent with embodiments of the present invention are described inU.S. Pat. Nos. 7,199,073, 7,226,886, 7,312,283, and 7,619,047, thedisclosures of which are incorporated herein by reference in theirentirety.

Moreover, the metallocene compound can comprise an unbridged dinuclearmetallocene such as those described in U.S. Pat. Nos. 7,919,639 and8,080,681, the disclosures of which are incorporated herein by referencein their entirety. The metallocene compound can comprise an unbridgedzirconium and/or hafnium based dinuclear metallocene compound. Forexample, the metallocene compound can comprise an unbridged zirconiumbased homodinuclear metallocene compound, or an unbridged hafnium basedhomodinuclear metallocene compound, or an unbridged zirconium and/orhafnium based heterodinuclear metallocene compound (i.e., a dinuclearcompound with two hafniums, or two zirconiums, or one zirconium and onehafnium).

Embodiments of this invention also are directed to catalyst compositionsand methods of preparing catalyst compositions in which two or moremetallocene compounds are employed, e.g., a dual metallocene catalystcomposition. Independently, each respective metallocene compound can beany bridged metallocene compound disclosed herein or any unbridgedmetallocene compound disclosed herein.

Activator-Supports

The present invention encompasses various catalyst compositionscontaining an activator-support, and various methods of preparingcatalyst compositions using an activator-support. In one embodiment, theactivator-support can comprise a solid oxide treated with anelectron-withdrawing anion. Alternatively, in another embodiment, theactivator-support can comprise a solid oxide treated with anelectron-withdrawing anion, the solid oxide containing a Lewis-acidicmetal ion. Non-limiting examples of suitable activator-supports aredisclosed in, for instance, U.S. Pat. Nos. 7,294,599, 7,601,665,7,884,163, and 8,309,485, which are incorporated herein by reference intheir entirety.

The solid oxide can encompass oxide materials such as alumina, “mixedoxides” thereof such as silica-alumina, coatings of one oxide onanother, and combinations and mixtures thereof. The mixed oxides such assilica-alumina can be single or multiple chemical phases with more thanone metal combined with oxygen to form the solid oxide. Examples ofmixed oxides that can be used to form an activator-support, eithersingly or in combination, can include, but are not limited to,silica-alumina, silica-titania, silica-zirconia, alumina-titania,alumina-zirconia, zinc-aluminate, alumina-boria, silica-boria,aluminophosphate-silica, titania-zirconia, and the like. The solid oxideused herein also can encompass oxide materials such as silica-coatedalumina, as described in U.S. Pat. No. 7,884,163.

Accordingly, in one embodiment, the solid oxide can comprise silica,alumina, silica-alumina, silica-coated alumina, aluminum phosphate,aluminophosphate, heteropolytungstate, titania, silica-titania,zirconia, silica-zirconia, magnesia, boria, zinc oxide, any mixed oxidethereof, or any combination thereof. In another embodiment, the solidoxide can comprise alumina, silica-alumina, silica-coated alumina,aluminum phosphate, aluminophosphate, heteropolytungstate, titania,silica-titania, zirconia, silica-zirconia, magnesia, boria, or zincoxide, as well as any mixed oxide thereof, or any mixture thereof. Inanother embodiment, the solid oxide can comprise silica, alumina,titania, zirconia, magnesia, boria, zinc oxide, any mixed oxide thereof,or any combination thereof. In yet another embodiment, the solid oxidecan comprise silica-alumina, silica-coated alumina, silica-titania,silica-zirconia, alumina-boria, or any combination thereof. In stillanother embodiment, the solid oxide can comprise alumina,silica-alumina, silica-coated alumina, or any mixture thereof;alternatively, alumina; alternatively, silica-alumina; or alternatively,silica-coated alumina.

The silica-alumina or silica-coated alumina solid oxide materials whichcan be used can have an silica content from about 5% to about 95% byweight. In one embodiment, the silica content of these solid oxides canbe from about 10% to about 80%, or from about 20% to about 70%, silicaby weight. In another embodiment, such materials can have silicacontents ranging from about 15% to about 60%, or from about 25% to about50%, silica by weight. The solid oxides contemplated herein can have anysuitable surface area, pore volume, and particle size, as would berecognized by those of skill in the art.

The electron-withdrawing component used to treat the solid oxide can beany component that increases the Lewis or Brønsted acidity of the solidoxide upon treatment (as compared to the solid oxide that is not treatedwith at least one electron-withdrawing anion). According to oneembodiment, the electron-withdrawing component can be anelectron-withdrawing anion derived from a salt, an acid, or othercompound, such as a volatile organic compound, that serves as a sourceor precursor for that anion. Examples of electron-withdrawing anions caninclude, but are not limited to, sulfate, bisulfate, fluoride, chloride,bromide, iodide, fluorosulfate, fluoroborate, phosphate,fluorophosphate, trifluoroacetate, triflate, fluorozirconate,fluorotitanate, phospho-tungstate, tungstate, molybdate, and the like,including mixtures and combinations thereof. In addition, other ionic ornon-ionic compounds that serve as sources for these electron-withdrawinganions also can be employed. It is contemplated that theelectron-withdrawing anion can be, or can comprise, fluoride, chloride,bromide, phosphate, triflate, bisulfate, or sulfate, and the like, orany combination thereof, in some embodiments provided herein. In otherembodiments, the electron-withdrawing anion can comprise sulfate,bisulfate, fluoride, chloride, bromide, iodide, fluorosulfate,fluoroborate, phosphate, fluorophosphate, trifluoroacetate, triflate,fluorozirconate, fluorotitanate, and the like, or combinations thereof.Yet, in other embodiments, the electron-withdrawing anion can comprisefluoride and/or sulfate.

The activator-support generally can contain from about 1 to about 25 wt.% of the electron-withdrawing anion, based on the weight of theactivator-support. In particular embodiments provided herein, theactivator-support can contain from about 1 to about 20 wt. %, from about2 to about 20 wt. %, from about 3 to about 20 wt. %, from about 2 toabout 15 wt. %, from about 3 to about 15 wt. %, from about 3 to about 12wt. %, or from about 4 to about 10 wt. %, of the electron-withdrawinganion, based on the total weight of the activator-support.

In an embodiment, the activator-support can comprise fluorided alumina,chlorided alumina, bromided alumina, sulfated alumina, phosphatedalumina, fluorided silica-alumina, chlorided silica-alumina, bromidedsilica-alumina, sulfated silica-alumina, phosphated silica-alumina,fluorided silica-zirconia, chlorided silica-zirconia, bromidedsilica-zirconia, sulfated silica-zirconia, fluorided silica-titania,fluorided silica-coated alumina, fluorided-chlorided silica-coatedalumina, sulfated silica-coated alumina, phosphated silica-coatedalumina, and the like, as well as any mixture or combination thereof. Inanother embodiment, the activator-support employed in the processes andcatalyst systems described herein can be, or can comprise, a fluoridedsolid oxide and/or a sulfated solid oxide and/or a phosphated solidoxide, non-limiting examples of which can include fluorided alumina,sulfated alumina, phosphated alumina, fluorided silica-alumina, sulfatedsilica-alumina, phosphated silica-alumina, fluorided silica-zirconia,fluorided silica-coated alumina, fluorided-chlorided silica-coatedalumina, sulfated silica-coated alumina, phosphated silica-coatedalumina, and the like, as well as combinations thereof. In yet anotherembodiment, the activator-support can comprise fluorided alumina;alternatively, chlorided alumina; alternatively, sulfated alumina;alternatively, phosphated alumina; alternatively, fluoridedsilica-alumina; alternatively, sulfated silica-alumina; alternatively,phosphated silica-alumina; alternatively, fluorided silica-zirconia;alternatively, chlorided silica-zirconia; alternatively, sulfatedsilica-coated alumina; alternatively, phosphated silica-coated alumina;alternatively, fluorided-chlorided silica-coated alumina; oralternatively, fluorided silica-coated alumina.

Various processes can be used to form activator-supports useful in thepresent invention. Methods of contacting the solid oxide with theelectron-withdrawing component, suitable electron withdrawing componentsand addition amounts, impregnation with metals or metal ions (e.g.,zinc, nickel, vanadium, titanium, silver, copper, gallium, tin,tungsten, molybdenum, zirconium, and the like, or combinations thereof),and various calcining procedures and conditions are disclosed in, forexample, U.S. Pat. Nos. 6,107,230, 6,165,929, 6,294,494, 6,300,271,6,316,553, 6,355,594, 6,376,415, 6,388,017, 6,391,816, 6,395,666,6,524,987, 6,548,441, 6,548,442, 6,576,583, 6,613,712, 6,632,894,6,667,274, 6,750,302, 7,294,599, 7,601,665, 7,884,163, and 8,309,485,which are incorporated herein by reference in their entirety. Othersuitable processes and procedures for preparing activator-supports(e.g., fluorided solid oxides, sulfated solid oxides, or phosphatedsolid oxides) are well known to those of skill in the art.

Organoaluminum Compounds

The present invention encompasses various catalyst compositionscontaining an organoaluminum compound, and various methods of preparingcatalyst compositions using an organoaluminum compound. More than oneorganoaluminum compound can be used. For instance, a mixture orcombination of two suitable organoaluminum compounds can be used in theprocesses and catalyst systems disclosed herein.

In some embodiments, suitable organoaluminum compounds can have theformula, (R^(Z))₃Al, wherein each R^(Z) independently can be analiphatic group having from 1 to 10 carbon atoms. For example, eachR^(Z) independently can be methyl, ethyl, propyl, butyl, hexyl, orisobutyl. In other embodiments, suitable organoaluminum compounds canhave the formula, Al(X⁷)_(m)(X⁸)_(3-m), wherein each X⁷ independentlycan be a hydrocarbyl; each X⁸ independently can be an alkoxide or anaryloxide, a halide, or a hydride; and m can be from 1 to 3, inclusive.Hydrocarbyl is used herein to specify a hydrocarbon radical group andincludes, for instance, aryl, alkyl, cycloalkyl, alkenyl, cycloalkenyl,cycloalkadienyl, alkynyl, aralkyl, aralkenyl, and aralkynyl groups. Inone embodiment, each X⁷ independently can be any hydrocarbyl having from1 to about 18 carbon atoms, or from 1 to about 8 carbon atoms, or analkyl having from 1 to 10 carbon atoms. For example, each X⁷independently can be methyl, ethyl, propyl, n-butyl, sec-butyl,isobutyl, or hexyl, and the like, in certain embodiments of the presentinvention. According to another embodiment of the present invention,each X⁸ independently can be an alkoxide or an aryloxide, any one ofwhich has from 1 to 18 carbon atoms, a halide, or a hydride. In yetanother embodiment of the present invention, each X⁸ can be selectedindependently from fluorine and chlorine. In the formula,Al(X⁷)_(m)(X⁸)_(3-m), m can be a number from 1 to 3 (inclusive) andtypically, m can be 3. The value of m is not restricted to be aninteger; therefore, this formula can include sesquihalide compounds orother organoaluminum cluster compounds.

Examples of organoaluminum compounds suitable for use in accordance withthe present invention can include, but are not limited to,trialkylaluminum compounds, dialkylaluminum halide compounds,dialkylaluminum alkoxide compounds, dialkylaluminum hydride compounds,and combinations thereof. Specific non-limiting examples of suitableorganoaluminum compounds can include trimethylaluminum (TMA),triethylaluminum (TEA), tri-n-propylaluminum (TNPA), tri-n-butylaluminum(TNBA), triisobutylaluminum (TIBA), tri-n-hexylaluminum,tri-n-octylaluminum, diisobutylaluminum hydride, diethylaluminumethoxide, diethylaluminum chloride, and the like, or combinationsthereof. In one embodiment, an organoaluminum compound used in theprocesses and catalyst systems disclosed herein can comprise (or consistessentially of, or consist of) triethylaluminum (TEA), while in anotherembodiment, an organoaluminum compound used in the processes andcatalyst systems disclosed herein can comprise (or consist essentiallyof, or consist of) triisobutylaluminum (TIBA). Yet, in anotherembodiment, a mixture of TEA and TIBA can be used as the organoaluminumcomponent in the processes described herein (or as the organoaluminumcomponent in the catalyst systems disclosed herein).

Olefin Monomers and Olefin Polymers

Olefin monomers contemplated herein typically include olefin compoundshaving from 2 to 30 carbon atoms per molecule and having at least oneolefinic double bond. Homopolymerization processes using a singleolefin, such as ethylene, propylene, butene, hexene, octene, and thelike, are encompassed, as well as copolymerization andterpolymerization, reactions using an olefin monomer with at least onedifferent olefinic compound. For example, resultant ethylene copolymers,or terpolymers, generally can contain a major amount of ethylene (>50mole percent) and a minor amount of comonomer (<50 mole percent), thoughthis is not a requirement. Comonomers that can be copolymerized withethylene often can have from 3 to 20 carbon atoms, or from 3 to 10carbon atoms, in their molecular chain.

Acyclic, cyclic, polycyclic, terminal (a), internal, linear, branched,substituted, unsubstituted, functionalized, and non-functionalizedolefins can be employed. For example, typical unsaturated compounds thatcan be polymerized to produce olefin polymers can include, but are notlimited to, ethylene, propylene, 1-butene, 2-butene, 3-methyl-1-butene,isobutylene, 1-pentene, 2-pentene, 3-methyl-1-pentene,4-methyl-1-pentene, 1-hexene, 2-hexene, 3-hexene, 3-ethyl-1-hexene,1-heptene, 2-heptene, 3-heptene, the four normal octenes (e.g.,1-octene), the four normal nonenes, the five normal decenes, and thelike, or mixtures of two or more of these compounds. Cyclic and bicyclicolefins, including but not limited to, cyclopentene, cyclohexene,norbornylene, norbornadiene, and the like, also can be polymerized asdescribed herein. Styrene also can be employed as a monomer or as acomonomer. In an embodiment, the olefin monomer can comprise a C₂-C₂₀olefin; alternatively, a C₂-C₂₀ α-olefin; alternatively, a C₂-C₁₂olefin; alternatively, a C₂-C₁₀ α-olefin; alternatively, ethylene,propylene, 1-butene, 1-hexene, or 1-octene; alternatively, ethylene orpropylene; alternatively, ethylene; or alternatively, propylene.

When a copolymer (or alternatively, a terpolymer) is desired, the olefinmonomer can be, for example, ethylene or propylene, which iscopolymerized with at least one comonomer (e.g., a C₂-C₂₀ α-olefin, aC₃-C₂₀ α-olefin). According to one embodiment, the olefin monomer in thepolymerization process can be ethylene. In this embodiment, examples ofsuitable olefin comonomers can include, but are not limited to,propylene, 1-butene, 2-butene, 3-methyl-1-butene, isobutylene,1-pentene, 2-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene,2-hexene, 3-ethyl-1-hexene, 1-heptene, 2-heptene, 3-heptene, 1-octene,1-decene, styrene, and the like, or combinations thereof. According toanother embodiment, the comonomer can comprise an α-olefin (e.g., aC₃-C₁₀ α-olefin), while in yet another embodiment, the comonomer cancomprise 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, styrene, orany combination thereof. For example, the comonomer can comprise1-butene, 1-hexene, 1-octene, or a combination thereof.

Generally, the amount of comonomer introduced into a polymerizationreactor to produce the copolymer can be from about 0.01 to about 50weight percent of the comonomer based on the total weight of the monomerand comonomer. According to another embodiment, the amount of comonomerintroduced into a polymerization reactor can be from about 0.01 to about40 weight percent comonomer based on the total weight of the monomer andcomonomer. In still another embodiment, the amount of comonomerintroduced into a polymerization reactor can be from about 0.1 to about35 weight percent comonomer based on the total weight of the monomer andcomonomer. Yet, in another embodiment, the amount of comonomerintroduced into a polymerization reactor can be from about 0.5 to about20 weight percent comonomer based on the total weight of the monomer andcomonomer.

While not intending to be bound by this theory, where branched,substituted, or functionalized olefins are used as reactants, it isbelieved that a steric hindrance can impede and/or slow thepolymerization reaction. Thus, branched and/or cyclic portion(s) of theolefin removed somewhat from the carbon-carbon double bond would not beexpected to hinder the reaction in the way that the same olefinsubstituents situated more proximate to the carbon-carbon double bondmight.

According to one embodiment, at least one monomer/reactant can beethylene (or propylene), so the polymerization reaction can be ahomopolymerization involving only ethylene (or propylene), or acopolymerization with a different acyclic, cyclic, terminal, internal,linear, branched, substituted, or unsubstituted olefin. In addition, themethods disclosed herein intend for olefin to also encompass diolefincompounds that include, but are not limited to, 1,3-butadiene, isoprene,1,4-pentadiene, 1,5-hexadiene, and the like.

Olefin polymers encompassed herein can include any polymer (or oligomer)produced from any olefin monomer (and optional comonomer(s)) describedherein. For example, the olefin polymer can comprise an ethylenehomopolymer, a propylene homopolymer, an ethylene copolymer (e.g.,ethylene/α-olefin, ethylene/1-butene, ethylene/1-hexene, orethylene/1-octene), a propylene copolymer, an ethylene terpolymer, apropylene terpolymer, and the like, including combinations thereof. Inone embodiment, the olefin polymer can be (or can comprise) an ethylenehomopolymer, an ethylene/1-butene copolymer, an ethylene/1-hexenecopolymer, or an ethylene/1-octene copolymer; or alternatively, anethylene/1-hexene copolymer. In another embodiment, the olefin polymercan be (or can comprise) a polypropylene homopolymer or apropylene-based copolymer. In some embodiments, the olefin polymer canhave a bimodal molecular weight distribution, while in otherembodiments, the olefin polymer can have a multimodal molecular weightdistribution. Yet, in still other embodiments, the olefin polymer canhave a unimodal molecular weight distribution.

Polymerization Reactor Systems and Processes

The disclosed catalyst systems and methods of their preparation areintended for any olefin polymerization process using various types ofpolymerization reactors, polymerization reactor systems, andpolymerization reaction conditions. As used herein, “polymerizationreactor” includes any polymerization reactor capable of polymerizingolefin monomers and comonomers (one or more than one comonomer) toproduce homopolymers, copolymers, terpolymers, and the like. The varioustypes of polymerization reactors include, but are not limited to, thosethat can be referred to as a batch reactor, slurry reactor, gas-phasereactor, solution reactor, high pressure reactor, tubular reactor,autoclave reactor, and the like, or combinations thereof. Suitablepolymerization conditions are used for the various reactor types. Gasphase reactors can comprise fluidized bed reactors or staged horizontalreactors. Slurry reactors can comprise vertical or horizontal loops.High pressure reactors can comprise autoclave reactors, tubularreactors, or combinations thereof, in parallel or in series. Reactortypes can include batch or continuous processes. Continuous processescan use intermittent or continuous product discharge. Polymerizationreactor systems and processes also can include partial or full directrecycle of unreacted monomer, unreacted comonomer, and/or diluent.

A polymerization reactor system can comprise a single reactor ormultiple reactors (for example, 2 reactors, or more than 2 reactors) ofthe same or different type. For example, the polymerization reactorsystem can comprise a slurry reactor, a gas-phase reactor, a solutionreactor, or a combination of two or more of these reactors. Productionof polymers in multiple reactors can include several stages in at leasttwo separate polymerization reactors interconnected by at least onetransfer device, making it possible to transfer the polymers resultingfrom the first polymerization reactor into the second reactor. Thedesired polymerization conditions in one of the reactors can bedifferent from the operating conditions of the other reactor(s).Alternatively, polymerization in multiple reactors can include themanual transfer of polymer from one reactor to subsequent reactors forcontinued polymerization. Multiple reactor systems can include anycombination including, but not limited to, multiple loop reactors,multiple gas phase reactors, a combination of loop and gas phasereactors, multiple high pressure reactors, or a combination of highpressure with loop and/or gas phase reactors. The multiple reactors canbe operated in series, in parallel, or both.

According to one embodiment, the polymerization reactor system cancomprise at least one loop slurry reactor comprising vertical orhorizontal loops. Monomer, diluent, catalyst, and comonomer can becontinuously fed into a loop reactor where polymerization occurs.Generally, continuous processes can comprise the continuous introductionof monomer/comonomer, a catalyst, and a diluent into a polymerizationreactor and the continuous removal from this reactor of a suspensioncomprising polymer particles and the diluent. Reactor effluent can beflashed to remove the solid polymer from the liquids that comprise thediluent, monomer and/or comonomer. Various technologies can be used forthis separation step including, but not limited to, flashing that caninclude any combination of heat addition and pressure reduction,separation by cyclonic action in either a cyclone or hydrocyclone, orseparation by centrifugation.

A typical slurry polymerization process (also known as the particle formprocess) is disclosed, for example, in U.S. Pat. Nos. 3,248,179,4,501,885, 5,565,175, 5,575,979, 6,239,235, 6,262,191, 6,833,415, and8,822,608, each of which is incorporated herein by reference in itsentirety.

Suitable diluents used in slurry polymerization include, but are notlimited to, the monomer being polymerized and hydrocarbons that areliquids under reaction conditions. Examples of suitable diluentsinclude, but are not limited to, hydrocarbons such as propane,cyclohexane, isobutane, n-butane, n-pentane, isopentane, neopentane, andn-hexane. Some loop polymerization reactions can occur under bulkconditions where no diluent is used.

According to yet another embodiment, the polymerization reactor systemcan comprise at least one gas phase reactor (e.g., a fluidized bedreactor). Such reactor systems can employ a continuous recycle streamcontaining one or more monomers continuously cycled through a fluidizedbed in the presence of the catalyst under polymerization conditions. Arecycle stream can be withdrawn from the fluidized bed and recycled backinto the reactor. Simultaneously, polymer product can be withdrawn fromthe reactor and new or fresh monomer can be added to replace thepolymerized monomer. Such gas phase reactors can comprise a process formulti-step gas-phase polymerization of olefins, in which olefins arepolymerized in the gaseous phase in at least two independent gas-phasepolymerization zones while feeding a catalyst-containing polymer formedin a first polymerization zone to a second polymerization zone.Representative gas phase reactors are disclosed in U.S. Pat. Nos.5,352,749, 4,588,790, 5,436,304, 7,531,606, and 7,598,327, each of whichis incorporated by reference in its entirety herein.

According to still another embodiment, the polymerization reactor systemcan comprise a high pressure polymerization reactor, e.g., can comprisea tubular reactor and/or an autoclave reactor. Tubular reactors can haveseveral zones where fresh monomer, initiators, or catalysts are added.Monomer can be entrained in an inert gaseous stream and introduced atone zone of the reactor. Initiators, catalysts, and/or catalystcomponents can be entrained in a gaseous stream and introduced atanother zone of the reactor. The gas streams can be intermixed forpolymerization. Heat and pressure can be employed appropriately toobtain optimal polymerization reaction conditions.

According to yet another embodiment, the polymerization reactor systemcan comprise a solution polymerization reactor wherein themonomer/comonomer are contacted with the catalyst composition bysuitable stirring or other means. A carrier comprising an inert organicdiluent or excess monomer can be employed. If desired, themonomer/comonomer can be brought in the vapor phase into contact withthe catalytic reaction product, in the presence or absence of liquidmaterial. The polymerization zone can be maintained at temperatures andpressures that will result in the formation of a solution of the polymerin a reaction medium. Agitation can be employed to obtain bettertemperature control and to maintain uniform polymerization mixturesthroughout the polymerization zone. Adequate means are utilized fordissipating the exothermic heat of polymerization.

The polymerization reactor system can further comprise any combinationof at least one raw material feed system, at least one feed system forcatalyst or catalyst components, and/or at least one polymer recoverysystem. Suitable reactor systems can further comprise systems forfeedstock purification, catalyst storage and preparation, extrusion,reactor cooling, polymer recovery, fractionation, recycle, storage,loadout, laboratory analysis, and process control. Depending upon thedesired properties of the olefin polymer, hydrogen can be added to thepolymerization reactor as needed (e.g., continuously or pulsed), and asdiscussed hereinabove.

Polymerization conditions that can be controlled for efficiency and toprovide desired polymer properties can include temperature, pressure,and the concentrations of various reactants. Polymerization temperaturecan affect catalyst productivity, polymer molecular weight, andmolecular weight distribution. A suitable polymerization temperature canbe any temperature below the de-polymerization temperature according tothe Gibbs Free energy equation. Typically, this includes from about 60°C. to about 280° C., for example, or from about 60° C. to about 120° C.,depending upon the type of polymerization reactor. In some reactorsystems, the polymerization temperature generally can be within a rangefrom about 70° C. to about 110° C., or from about 75° C. to about 95° C.

Suitable pressures will also vary according to the reactor andpolymerization type. The pressure for liquid phase polymerizations in aloop reactor typically can be less than 1000 psig. The pressure for gasphase polymerization can be in the 200 to 500 psig range. High pressurepolymerization in tubular or autoclave reactors generally can beconducted at about 20,000 to 75,000 psig. Polymerization reactors alsocan be operated in a supercritical region occurring at generally highertemperatures and pressures. Operation above the critical point of apressure/temperature diagram (supercritical phase) can offer advantagesto the polymerization reaction process.

Also encompassed herein are olefin polymerization processes utilizingany of the catalyst compositions described herein. One such process cancomprise contacting a catalyst composition with an olefin monomer andoptionally an olefin comonomer in a polymerization reactor system underpolymerization conditions to produce an olefin polymer. Generally, thepolymerization process can utilize any olefin monomer and optionalcomonomer disclosed herein, and the catalyst composition employed can bea single (or dual) metallocene catalyst system utilizing, for instance,any of the metallocene compounds, any of activator-supports, and any ofthe organoaluminum compounds disclosed herein, and the catalyst systemcan be prepared by any of the processes disclosed herein.

A metallocene-based catalyst composition, in one embodiment, can beproduced by a process comprising contacting, in any order, (a) anactivator-support, (b) a mixture comprising a metallocene compound andcyclohexene, 1-hexene, or a mixture of cyclohexene and 1-hexene, and (c)an organoaluminum compound, to produce the catalyst composition. Ametallocene-based catalyst composition, in another embodiment, can beproduced by a process comprising (i) contacting an activator-support andan organoaluminum compound for a first period of time to form aprecontacted mixture, and (ii) contacting the precontacted mixture witha second mixture comprising a metallocene compound and cyclohexene,1-hexene, or a mixture thereof, for a second period of time to form thecatalyst composition.

Polymerization processes consistent with this invention can comprisecontacting such catalyst compositions (i.e., prepared using cyclohexene,1-hexene, or a mixture of cyclohexene and 1-hexene) with an olefinmonomer and optionally an olefin comonomer in a polymerization reactorsystem under polymerization conditions to produce an olefin polymer. Asdescribed herein, the catalyst activities of these catalystcompositions, unexpectedly, can be greater than that of catalyst systemsobtained by using toluene, under the same catalyst preparationconditions, and when tested under the same polymerization conditions.

This invention is also directed to, and encompasses, the polymersproduced by any of the polymerization processes disclosed herein.Beneficially, the polymer (e.g., an ethylene polymer) can containsubstantially no residual toluene, i.e., less than 5 ppm by weight. Insome embodiments, the polymer can contain less than 2 ppm by weighttoluene, or further, no measurable amount of toluene. Since the mixtureof the metallocene compound and cyclohexene and/or 1-hexene used toproduce the catalyst system disclosed herein does not require toluene,which recent regulations indicate may have a number of hazardsassociated with it, this is a potential benefit of the presentinvention.

Also beneficially, and unexpectedly, the polymers produced using thedisclosed catalyst systems can have lower levels of residual solvents byusing cyclohexene instead of toluene. While not wishing to be bound bytheory, it is believed that the cyclohexene may be more easily removedfrom the polymer than toluene (e.g., when present at the same level),thus resulting in less residual solvents present in the finishedpolymer. Accordingly, an olefin polymer produced using thepolymerization processes and catalyst systems disclosed herein withcyclohexene (and 1-hexene, if used) can have lower levels of residualsolvents than that of an olefin polymer obtained using a catalyst systemprepared using toluene (and 1-hexene, if used), under the same catalystpreparation and polymerization conditions.

Articles of manufacture can be formed from, and/or can comprise, thepolymers (e.g., ethylene copolymers) of this invention and, accordingly,are encompassed herein. For example, articles that can comprise polymersof this invention include, but are not limited to, an agricultural film,an automobile part, a bottle, a drum, a fiber or fabric, a foodpackaging film or container, a food service article, a fuel tank, ageomembrane, a household container, a liner, a molded product, a medicaldevice or material, a pipe, a sheet or tape, a toy, and the like.Various processes can be employed to form these articles. Non-limitingexamples of these processes include injection molding, blow molding,rotational molding, film extrusion, sheet extrusion, profile extrusion,thermoforming, and the like. Additionally, additives and modifiers areoften added to these polymers in order to provide beneficial polymerprocessing or end-use product attributes. Such processes and materialsare described in Modern Plastics Encyclopedia, Mid-November 1995 Issue,Vol. 72, No. 12; and Film Extrusion Manual—Process, Materials,Properties, TAPPI Press, 1992; the disclosures of which are incorporatedherein by reference in their entirety.

Also contemplated herein is a method for forming or preparing an articleof manufacture comprising a polymer produced by any of thepolymerization processes disclosed herein. For instance, a method cancomprise (i) contacting any catalyst composition disclosed herein withan olefin monomer and an optional olefin comonomer under polymerizationconditions in a polymerization reactor system to produce an olefinpolymer (the catalyst composition can be prepared in accordance with anyprocess disclosed herein); and (ii) forming an article of manufacturecomprising the olefin polymer. The forming step can comprise blending,melt processing, extruding, molding, or thermoforming, and the like,including combinations thereof.

EXAMPLES

Embodiments of the invention are further illustrated by the followingexamples, which are not to be construed in any way as imposinglimitations to the scope of this invention described herein. Variousother aspects, embodiments, modifications, and equivalents thereofwhich, after reading the description herein, can suggest themselves toone of ordinary skill in the art without departing from the spirit ofthe present invention or the scope of the appended claims.

Sulfated alumina activator-supports were prepared as follows. Bohemitewas obtained from W.R. Grace & Company under the designation “Alumina A”and having a surface area of about 300 m²/g and a pore volume of about1.3 mL/g. This material was obtained as a powder having an averageparticle size of about 100 microns. This material was impregnated toincipient wetness with an aqueous solution of ammonium sulfate to equalabout 15% sulfate. The pore filling or “incipient wetness” impregnationtechnique used is a method in which the solution is mixed with the drysupport until the pores are filled. The definition of the end point ofthis method may vary somewhat from laboratory to laboratory so that animpregnated catalyst could have a completely dry appearance or a stickysnow-like appearance. However, in no instances would there be any freeflowing liquid present when the incipient wetness method is employed.This mixture was then placed in a flat pan and allowed to dry undervacuum at approximately 110° C. for about 16 hours. To calcine theresultant powdered mixture, the material was fluidized in a stream ofdry air at about 550° C. for about 6 hours. Afterward, the sulfatedalumina was collected and stored under dry nitrogen, and was usedwithout exposure to the atmosphere.

The polymerization experiments were performed as follows. First, 0.6mmol of triisobutylaluminum (TIBA, 0.6 mL of a 1M solution in heptane)was added to the reactor while venting isobutane vapor. Next, 100 mg ofthe sulfated alumina activator-support was added to the reactor,followed by a metallocene solution containing 2 mg of the respectivemetallocene compound (metallocene concentration ranged from about 0.2 toabout 1.4 wt. %). The metallocene solutions were prepared by dissolvingthe desired amount of the metallocene compound in the respective solventor blend of solvents. The reactor contents were mixed, the charge portwas closed, and 2 L of isobutane were added to the reactor. The contentsof the reactor were stirred and heated to the desired polymerizationreaction temperature of 90° C., and ethylene was then introduced intothe reactor (no hydrogen or comonomer was used). Ethylene was fed ondemand to maintain the target pressure of 420 psig pressure for the 30min length of each polymerization experiment. The reactor was maintainedat the desired reaction temperature throughout the experiment by anautomated heating-cooling system.

The chemical structures for the metallocene compounds used in theexamples that follow are provided below (stereochemistry is not shown).

Examples 1-8 Catalyst Activity Improvement Via the Use of a Solution ofa Metallocene Compound and Cyclohexene Alone or in Combination with1-Hexene to Prepare the Catalyst System, Instead of Using Toluene Aloneor in Combination with 1-Hexene

Table I summarizes certain catalyst system components and the catalystactivity results (grams of polyethylene produced per gram of metallocenecompound per hour) for Examples 1-8. As shown in Table I, andunexpectedly, using a blend of 20% cyclohexene and 80% 1-hexene insteadof 100% toluene as the solvent for the metallocene during the catalystpreparation process resulted in a 21% improvement in activity for MET-A(Examples 1-2) and a 3% improvement in activity for MET-B (Examples7-8). Furthermore, and quite surprisingly, using cyclohexene instead oftoluene as the solvent for the metallocene during the catalystpreparation process resulted in a 36% improvement in activity (Examples3-4), while using a blend of 20% cyclohexene and 80% 1-hexene instead of20% toluene and 80% 1-hexene as the solvent for the metallocene duringthe catalyst preparation process resulted in an 18% improvement inactivity (Examples 5-6).

Examples 9-11 Solvent Impact on Metallocene Precipitation

Metallocene solutions of MET-A in a blend of toluene and 1-hexene,cyclohexene, and a blend of cyclohexene and 1-hexene were prepared atmetallocene concentrations in the 0.3-0.4 wt. % range. Table IIsummarizes the results. Example 9 showed visible precipitation at 8° C.in the blend of toluene and 1-hexene, while unexpectedly, there was novisible precipitation in the solution with cyclohexene (Example 10) orin the blend of cyclohexene and 1-hexene (Example 11) at temperaturesbelow 0° C.

Examples 12-13 Solvent Impact on the Level of Residual Solvent inPolyethylene

Polyethylene was produced as described in Examples 1-8 using catalystsystems in which toluene was the solvent for the metallocene (Example12) and cyclohexene was the solvent for the metallocene (Example 13).The polymer fluff produced in Examples 12-13 was not dried to remove anyresidual solvent, and was tested for solvent level (ppm by weight) usingheadspace gas chromatography (GC)—this is denoted as the initial solventlevel in Table III. After drying the polymer fluff at 60° C. underreduced pressure for 2 hours to remove residual solvent, the polymerfluff was again tested for solvent level (ppm by weight) using headspaceGC—this is denoted as the final solvent level in Table III. Quitesurprisingly, cyclohexene present in the polymer was easier to removefrom the polymer than the toluene: 61.8% of the cyclohexene was removed,versus 39.8% of the toluene, under the same test conditions. Thus, notonly can cyclohexene replace toluene as the catalyst solvent, but thepolymer produced can have lower levels of residual solvents.

The headspace GC was performed using an AutoDesorb Short Path ThermalDesorption system (Scientific Instrument Services, Inc.) sitting atopthe split injection port of a gas chromatograph (Agilent Technologies,Model 6890). The gas chromatograph was interfaced to a mass spectrometer(Agilent Technologies, Model 5973 Mass Selective Detector). Gaschromatograph and mass selective detector (MSD) instrument parametersare shown below.

GC Parameters Column J&W DB-5MS Split Ratio 10:1 Column Length 60 mInjector Temperature 250° C. Column Internal 0.25 mm Oven Initial 35° C.Diameter Temperature Column Phase 0.25 micron Oven Initial Time 5minutes Thickness Column Helium Oven Temperature 6° C./minute CarrierGas Ramp #1 Carrier Gas Constant Flow Oven Final 300° C. Flow ModeTemperature #1 Carrier Gas 1 mL/minute Oven Final 0 minutes FlowrateTemperature Hold Time Injection type Split Oven to MSD interface 300° C.Temperature MSD parameters Acquisition Mode Scan Scan Range 12-500 m/zIonization Mode Electron Quadrapole 200° C. Impact TemperatureIonization 70 eV Source Temperature 230° C. Potential

The AutoDesorb Short Path Thermal Desorption system utilized a 4″×¼″Silico-Steel coated stainless steel sample tube with an internaldiameter of 3 mm. Attached to one end of the tube was a stainless steelneedle approximately 1½″ long. The other end of the tube was coupled tothe AutoDesorb sampler. During the thermal desorption process, the tubewas held vertically over the GC injection port by the AutoDesorb samplerwith the needle penetrating the injection port septum so that allvolatilized components from sample inside the tube entered directly intothe GC injection port through the short needle path. A cryofocuser wasattached to the GC column approximately 2″ below the injection portinside the GC oven so that all volatilized components were trapped andfocused on the GC column during the entire desorption/volatilizationprocess. During the desorption/volatilization process, helium flowedthrough the tube at a flowrate of approximately 10 mL/min to sweepvolatilized components into the GC injection port. At the end of thedesorption/volatilization process, a heater embedded within thecryofocuser rapidly heated the column where cryofocusing occurred andthe gas chromatographic run started.

Prior to polymer sample introduction into AutoDesorb sample tubes, asmall plug of silianized glass wool was placed into each tube. A set ofsix tubes was then conditioned at 400° C. under continuous nitrogen flowfor four hours. After conditioning, at least one tube from each set wasanalyzed as a blank using the same methodology as used for samples toverify the cleanliness of the tube set.

Sample preparation consisted of placing 20 to 60 mg, accurately weighed,of small polymer sample pieces inside an AutoDesorb sample tube wherethey were held in place at the approximate linear center of the tube bythe glass wool plug. When samples were in pellet form, 4-5 pelletschosen at random points within the original sample container were usedto obtain a representative aliquot. After all of the pellets were cutinto smaller pieces, a random sampling of the smaller cut pieces wereutilized to weigh the amount of sample needed. The prepared sample tubeswere placed into the AutoDesorb carousel for subsequent analysis.

Each prepared sample tube was analyzed automatically according to thesteps and conditions shown below.

Step 1 Heat tube heater blocks to 150° C. Step 2 Cool cryofocuser to−130° C. Step 3 Purge tube contents at room temperature for 1 minutewith helium to remove residual air and moisture. Step 4 Insert tubeneedle into GC injection port. Step 5 Check that all GC inlet and columnpressures are correct. This indicates that helium is flowing throughtube at the correct flowrate. Step 6 Clamp tube heater blocks aroundtube to heat tube instantaneously to 150° C. Step 7 Hold tube at 150° C.with needle inside GC injection port for 10 minutes. During this time,the polymer sample pieces melt and volatile components are swept fromthe tube and cryogenically trapped at the head of the GC column. Step 8Remove heater blocks from tube and remove tube needle from GC injectionport. Step 9 Rapidly heat cryofocuser to 200° C. to release focusedvolatile components for GC column separation. Step 10 Start GCinstrument run and collect chromatographic/mass spectrometric data forseparated volatile components.

TABLE I Summary of Examples 1-8. Metallocene Activity ActivityConcentration (g PE/g Improvement Example Solvent System Metallocene(wt. %) MET/hr) (%) 1 100% Toluene MET-A 0.22 259,000 21.2 2 20%Cyclohexene/ MET-A 0.33 314,000 80% 1-hexene 3 100% Toluene MET-A 0.22188,700 36.4 4 100% Cyclohexene MET-A 1.40 257,400 5 20% Toluene/ MET-A0.35 186,100 18.2 80% 1-hexene 6 20% Cyclohexene/ MET-A 0.33 220,000 80%1-hexene 7 100 % Toluene MET-B 0.20 138,200 2.9 8 20% Cyclohexene/ MET-B0.18 142,200 80% 1-hexene

TABLE II Summary of Examples 9-11. Metallo- cene Concen- Tem- Pre- Ex-Metallo- tration perature cipitate ample Solvent System cene (wt. %) (°C.) Visible?  9 20% Toluene/ MET-A 0.35 8 Yes 80% 1-hexene 10 100%Cyclohexene MET-A 0.40 −21 No 11 20% Cyclohexene/ MET-A 0.33 −5 No 80%1-hexene

TABLE III Summary of Examples 12-13. Initial Solvent Final SolventDecrease in Example Solvent System Metallocene Level (ppm) Level (ppm)Solvent (%) 12 100% Toluene MET-A 24.1 14.5 39.8 13 100% CyclohexeneMET-A 20.7  7.9 61.8

The invention is described above with reference to numerous aspects andembodiments, and specific examples. Many variations will suggestthemselves to those skilled in the art in light of the above detaileddescription. All such obvious variations are within the full intendedscope of the appended claims. Other embodiments of the invention caninclude, but are not limited to, the following (embodiments aredescribed as “comprising” but, alternatively, can “consist essentiallyof” or “consist of”):

Embodiment 1

A process to produce a catalyst composition, the process comprisingcontacting, in any order:

-   -   (a) an activator-support;    -   (b) a mixture comprising cyclohexene and a metallocene compound;        and    -   (c) an organoaluminum compound;        to produce the catalyst composition.

Embodiment 2

The process defined in embodiment 1, wherein the mixture comprisescyclohexene, 1-hexene, and the metallocene compound.

Embodiment 3

The process defined in embodiment 2, wherein the weight ratio of1-hexene to cyclohexene (1-hexene:cyclohexene) in the mixture is in anyrange of weight ratios disclosed herein, e.g., from about 90:10 to about20:80, from about 90:10 to about 50:50, or from about 85:15 to about60:40.

Embodiment 4

The process defined in any one of the preceding embodiments, wherein theactivator-support, the mixture comprising cyclohexene and themetallocene compound (and 1-hexene, if used), and the organoaluminumcompound are contacted for any time period sufficient to form thecatalyst composition, e.g., from about 1 sec to about 48 hr, from about30 sec to about 6 hr, at least about 5 sec, or at least about 1 min.

Embodiment 5

The process defined in any one of the preceding embodiments, wherein theactivator-support is present as a slurry of the activator-support in afirst diluent.

Embodiment 6

The process defined in embodiment 5, wherein the first diluent comprisesany suitable non-polar hydrocarbon.

Embodiment 7

The process defined in embodiment 5, wherein the first diluent comprisespropane, cyclohexane, isobutane, n-butane, n-pentane, isopentane,neopentane, n-hexane, or combinations thereof.

Embodiment 8

The process defined in embodiment 5, wherein the first diluent comprisescyclohexene, 1-hexene, or both.

Embodiment 9

The process defined in any one of embodiments 1-4, wherein theactivator-support is present as a dry solid.

Embodiment 10

The process defined in any one of embodiments 1-9, wherein the mixturecomprising cyclohexene and the metallocene compound (and 1-hexene, ifused) is a solution, i.e., the metallocene compound is substantiallydissolved at standard temperature and pressure.

Embodiment 11

The process defined in any one of embodiments 1-9, wherein the mixturecomprising cyclohexene and the metallocene compound (and 1-hexene, ifused) is a slurry, i.e., the metallocene compound is not dissolved atstandard temperature and pressure.

Embodiment 12

The process defined in any one of the preceding embodiments, wherein theorganoaluminum compound is present as a solution in any suitablehydrocarbon solvent.

Embodiment 13

The process defined in embodiment 12, wherein the hydrocarbon solventcomprises cyclohexane, isobutane, n-butane, n-pentane, isopentane,neopentane, hexane, heptane, or combinations thereof.

Embodiment 14

A catalyst composition produced by the process defined in any one of thepreceding embodiments.

Embodiment 15

A catalyst composition comprising:

-   -   (A) an activator-support;    -   (B) an organoaluminum compound;    -   (C) a metallocene compound; and    -   (D) cyclohexene.

Embodiment 16

A catalyst composition comprising:

-   -   (A) an activator-support;    -   (B) an organoaluminum compound;    -   (C) a metallocene compound;    -   (D) cyclohexene; and    -   (E) 1-hexene.

Embodiment 17

The process or composition defined in any one of embodiments 1-16,wherein an activity of the catalyst composition is greater (by anyamount disclosed herein, e.g., at least about 1%, at least about 10%, atleast about 25%, from about 1% to about 100%, or from about 5% to about50%) than that of a catalyst system obtained by using toluene (ortoluene and 1-hexene) instead of cyclohexene, under the same catalystpreparation and polymerization conditions.

Embodiment 18

The process or composition defined in any one of embodiments 2-16,wherein an activity of the catalyst composition is greater (by anyamount disclosed herein, e.g., at least about 1%, at least about 10%, atleast about 25%, from about 1% to about 100%, or from about 5% to about50%) than that of a catalyst system obtained by using toluene and1-hexene (or toluene) instead of cyclohexene and 1-hexene, under thesame catalyst preparation and polymerization conditions.

Embodiment 19

The process or composition defined in any one of embodiments 2-18,wherein the mixture comprising cyclohexene, 1-hexene, and themetallocene compound has less precipitation of the metallocene compoundand/or the metallocene compound precipitates at a lower temperature thanthat of a mixture containing toluene, 1-hexene, and the metallocenecompound, when compared at the same metallocene loading, e.g., there issubstantially no precipitation of the mixture comprising cyclohexene,1-hexene, and the metallocene compound at 0° C.

Embodiment 20

A process to produce a catalyst composition, the process comprising:

(i) contacting an activator-support and an organoaluminum compound for afirst period of time to form a precontacted mixture; and

(ii) contacting the precontacted mixture with a second mixturecomprising cyclohexene and a metallocene compound for a second period oftime to form the catalyst composition.

Embodiment 21

The process defined in embodiment 20, wherein the second mixturecomprises cyclohexene, 1-hexene, and the metallocene compound.

Embodiment 22

The process defined in embodiment 21, wherein the weight ratio of1-hexene to cyclohexene (1-hexene:cyclohexene) in the second mixture isin any range of weight ratios disclosed herein, e.g., from about 90:10to about 20:80, from about 90:10 to about 50:50, or from about 85:15 toabout 60:40.

Embodiment 23

The process defined in any one of embodiments 20-22, wherein the firstperiod of time is any time period sufficient to form the precontactedmixture, e.g., from about 10 sec to about 48 hr, from about 30 sec toabout 6 hr, at least about 5 sec, or at least about 1 min.

Embodiment 24

The process defined in any one of embodiments 20-23, wherein the secondperiod of time is any time period sufficient to form the catalystcomposition, e.g., from about 1 sec to about 48 hr, from about 30 sec toabout 6 hr, at least about 5 sec, or at least about 1 min.

Embodiment 25

The process defined in any one of embodiments 20-24, wherein step (ii)comprises contacting the precontacted mixture, the second mixture, andan additional organoaluminum compound.

Embodiment 26

The process defined in any one of embodiments 20-25, wherein theactivator-support is present as a slurry of the activator-support in afirst diluent.

Embodiment 27

The process defined in embodiment 26, wherein the first diluentcomprises any suitable non-polar hydrocarbon.

Embodiment 28

The process defined in embodiment 26, wherein the first diluentcomprises propane, cyclohexane, isobutane, n-butane, n-pentane,isopentane, neopentane, n-hexane, or combinations thereof.

Embodiment 29

The process defined in embodiments 26, wherein the first diluentcomprises cyclohexene, 1-hexene, or both.

Embodiment 30

The process defined in any one of embodiments 20-25, wherein theactivator-support is present as a dry solid.

Embodiment 31

The process defined in any one of embodiments 20-30, wherein the mixturecomprising cyclohexene and the metallocene compound (and 1-hexene, ifused) is a solution, i.e., the metallocene compound is substantiallydissolved at standard temperature and pressure.

Embodiment 32

The process defined in any one of embodiments 20-30, wherein the mixturecomprising cyclohexene and the metallocene compound (and 1-hexene, ifused) is a slurry, i.e., the metallocene compound is not dissolved atstandard temperature and pressure.

Embodiment 33

The process defined in any one of embodiments 20-32, wherein theorganoaluminum compound is present as a solution in any suitablehydrocarbon solvent.

Embodiment 34

The process defined in embodiment 33, wherein the hydrocarbon solventcomprises cyclohexane, isobutane, n-butane, n-pentane, isopentane,neopentane, hexane, heptane, or combinations thereof.

Embodiment 35

A catalyst composition produced by the process defined in any one ofembodiments 20-34.

Embodiment 36

A catalyst composition comprising:

(I) a precontacted mixture comprising:

-   -   an activator-support, and    -   an organoaluminum compound;

(II) a metallocene compound; and

(III) cyclohexene.

Embodiment 37

A catalyst composition comprising:

(I) a precontacted mixture comprising:

-   -   an activator-support, and    -   an organoaluminum compound;

(II) a metallocene compound;

(III) cyclohexene; and

(IV) 1-hexene.

Embodiment 38

The process or composition defined in any one of embodiments 20-37,wherein an activity of the catalyst composition is greater (by anyamount disclosed herein, e.g., at least about 1%, at least about 10%, atleast about 25%, from about 1% to about 100%, or from about 5% to about50%) than that of a catalyst system obtained by using toluene (ortoluene and 1-hexene) instead of cyclohexene, under the same catalystpreparation and polymerization conditions.

Embodiment 39

The process or composition defined in any one of embodiments 21-37,wherein an activity of the catalyst composition is greater (by anyamount disclosed herein, e.g., at least about 1%, at least about 10%, atleast about 25%, from about 1% to about 100%, or from about 5% to about50%) than that of a catalyst system obtained by using toluene and1-hexene (or toluene) instead of cyclohexene and 1-hexene, under thesame catalyst preparation and polymerization conditions.

Embodiment 40

The process or composition defined in any one of embodiments 20-39,wherein an activity of the catalyst composition is greater (by anyamount disclosed herein, e.g., at least about 1%, at least about 10%, atleast about 25%, from about 1% to about 100%, or from about 5% to about50%) than that of a catalyst system obtained by first combining theactivator-support and the second mixture, and then combining theorganoaluminum compound, under the same polymerization conditions.

Embodiment 41

The process or composition defined in any one of embodiments 21-40,wherein the second mixture comprising cyclohexene, 1-hexene, and themetallocene compound has less precipitation of the metallocene compoundand/or the metallocene compound precipitates at a lower temperature thanthat of a mixture containing toluene, 1-hexene, and the metallocenecompound, when compared at the same metallocene loading, e.g., there issubstantially no precipitation of the mixture comprising cyclohexene,1-hexene, and the metallocene compound at 0° C.

Embodiment 42

The process or composition defined in any one of embodiments 1-41,wherein the activator-support comprises a solid oxide treated with anelectron-withdrawing anion, for example, comprising any solid oxidetreated with any electron-withdrawing anion disclosed herein.

Embodiment 43

The process or composition defined in embodiment 42, wherein the solidoxide comprises silica, alumina, silica-alumina, silica-coated alumina,aluminum phosphate, aluminophosphate, heteropolytungstate, titania,zirconia, magnesia, boria, zinc oxide, a mixed oxide thereof, or anymixture thereof and the electron-withdrawing anion comprises sulfate,bisulfate, fluoride, chloride, bromide, iodide, fluorosulfate,fluoroborate, phosphate, fluorophosphate, trifluoroacetate, triflate,fluorozirconate, fluorotitanate, phospho-tungstate, or any combinationthereof.

Embodiment 44

The process or composition defined in any one of embodiments 1-41,wherein the activator-support comprises a fluorided solid oxide, asulfated solid oxide, a phosphated solid oxide, or a combinationthereof.

Embodiment 45

The process or composition defined in any one of embodiments 1-35,wherein the activator-support comprises fluorided alumina, chloridedalumina, bromided alumina, sulfated alumina, phosphated alumina,fluorided silica-alumina, chlorided silica-alumina, bromidedsilica-alumina, sulfated silica-alumina, phosphated silica-alumina,fluorided silica-zirconia, chlorided silica-zirconia, bromidedsilica-zirconia, sulfated silica-zirconia, fluorided silica-titania,fluorided silica-coated alumina, fluorided-chlorided silica-coatedalumina, sulfated silica-coated alumina, phosphated silica-coatedalumina, or any combination thereof.

Embodiment 46

The process or composition defined in any one of embodiments 1-41,wherein the activator-support comprises fluorided alumina, fluoridedsilica-alumina, fluorided silica-zirconia, fluorided silica-coatedalumina, fluorided-chlorided silica-coated alumina, or any combinationthereof (e.g., fluorided silica-coated alumina).

Embodiment 47

The process or composition defined in any one of embodiments 1-41,wherein the activator-support comprises sulfated alumina, sulfatedsilica-alumina, sulfated silica-coated alumina, or any combinationthereof (e.g., sulfated alumina).

Embodiment 48

The process or composition defined in any one of embodiments 1-47,wherein the activator-support further comprises any metal or metal iondisclosed herein, e.g., zinc, nickel, vanadium, titanium, silver,copper, gallium, tin, tungsten, molybdenum, zirconium, or anycombination thereof.

Embodiment 49

The process or composition defined in any one of embodiments 1-48,wherein the organoaluminum compound comprises any organoaluminumcompound disclosed herein.

Embodiment 50

The process or composition defined in any one of embodiments 1-49,wherein the organoaluminum compound comprises trimethylaluminum,triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum,triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum,diisobutylaluminum hydride, diethylaluminum ethoxide, diethylaluminumchloride, or any combination thereof.

Embodiment 51

The process or composition defined in embodiment 49 or 50, wherein theorganoaluminum compound comprises triethylaluminum.

Embodiment 52

The process or composition defined in embodiment 49 or 50, wherein theorganoaluminum compound comprises triisobutylaluminum.

Embodiment 53

The process or composition defined in any one of embodiments 1-52,wherein the catalyst composition is substantially free of aluminoxanecompounds, organoboron or organoborate compounds, ionizing ioniccompounds, or combinations thereof.

Embodiment 54

The process or composition defined in any one of embodiments 1-53,wherein the metallocene compound comprises a bridged metallocenecompound, e.g., any bridged metallocene compound disclosed herein.

Embodiment 55

The process or composition defined in any one of embodiments 1-54,wherein the metallocene compound comprises a bridged zirconium basedmetallocene compound with a fluorenyl group, and with no aryl groups onthe bridging group.

Embodiment 56

The process or composition defined in any one of embodiments 1-54,wherein the metallocene compound comprises a bridged zirconium basedmetallocene compound with a cyclopentadienyl group and a fluorenylgroup, and with no aryl groups on the bridging group.

Embodiment 57

The process or composition defined in any one of embodiments 1-54,wherein the metallocene compound comprises a bridged zirconium orhafnium based metallocene compound with a fluorenyl group, and an arylgroup on the bridging group.

Embodiment 58

The process or composition defined in any one of embodiments 1-54,wherein the metallocene compound comprises a bridged zirconium orhafnium based metallocene compound with a cyclopentadienyl group andfluorenyl group, and an aryl group on the bridging group.

Embodiment 59

The process or composition defined in any one of embodiments 1-54,wherein the metallocene compound comprises a bridged zirconium basedmetallocene compound with a fluorenyl group, and an aryl group on thebridging group.

Embodiment 60

The process or composition defined in any one of embodiments 1-54,wherein the metallocene compound comprises a bridged hafnium basedmetallocene compound with a fluorenyl group, and an aryl group on thebridging group.

Embodiment 61

The process or composition defined in any one of embodiments 57-60,wherein the aryl group is a phenyl group.

Embodiment 62

The process or composition defined in any one of embodiments 1-54,wherein the metallocene compound comprises a bridged zirconium orhafnium based metallocene compound with a cyclopentadienyl group and afluorenyl group, and with an alkenyl substituent.

Embodiment 63

The process or composition defined in any one of embodiments 1-54,wherein the metallocene compound comprises a bridged zirconium orhafnium based metallocene compound with two indenyl groups.

Embodiment 64

The process or composition defined in any one of embodiments 1-54,wherein the metallocene compound comprises a bridged zirconium basedmetallocene compound with two indenyl groups.

Embodiment 65

The process or composition defined in any one of embodiments 63-64,wherein the bridging group contains a silicon atom.

Embodiment 66

The process or composition defined in any one of embodiments 1-53,wherein the metallocene compound comprises an unbridged metallocenecompound, e.g., any unbridged metallocene compound disclosed herein.

Embodiment 67

The process or composition defined in any one of embodiments 1-53,wherein the metallocene compound comprises an unbridged zirconium orhafnium based metallocene compound containing two cyclopentadienylgroups, two indenyl groups, or a cyclopentadienyl and an indenyl group.

Embodiment 68

The process or composition defined in any one of embodiments 1-53,wherein the metallocene compound comprises an unbridged zirconium basedmetallocene compound containing two cyclopentadienyl groups, two indenylgroups, or a cyclopentadienyl and an indenyl group.

Embodiment 69

The process or composition defined in any one of embodiments 1-53,wherein the metallocene compound comprises an unbridged zirconium basedhomodinuclear metallocene compound.

Embodiment 70

The process or composition defined in any one of embodiments 1-53,wherein the metallocene compound comprises an unbridged hafnium basedhomodinuclear metallocene compound.

Embodiment 71

The process or composition defined in any one of embodiments 1-53,wherein the metallocene compound comprises an unbridged heterodinuclearmetallocene compound.

Embodiment 72

The process or composition defined in any one of embodiments 1-71,wherein the weight ratio of the metallocene compound to theactivator-support is in any range of weight ratios disclosed herein,e.g., from about 1:1 to about 1:1,000,000, from about 1:10 to about1:10,000, or from about 1:20 to about 1:1000.

Embodiment 73

The process or composition defined in any one of embodiments 1-72,wherein the weight ratio of the activator-support to the organoaluminumcompound is in any range of weight ratios disclosed herein, e.g., fromabout 1:5 to about 1000:1, from about 1:3 to about 200:1, or from about1:1 to about 100:1.

Embodiment 74

An olefin polymerization process, the process comprising contacting thecatalyst composition defined in any one of embodiments 1-73 with anolefin monomer and an optional olefin comonomer in a polymerizationreactor system under polymerization conditions to produce an olefinpolymer.

Embodiment 75

The process defined in embodiment 74, wherein the olefin monomercomprises any olefin monomer disclosed herein, e.g., any C₂-C₂₀ olefin.

Embodiment 76

The process defined in embodiment 74, wherein the olefin monomer and theoptional olefin comonomer independently comprise a C₂-C₂₀ alpha-olefin.

Embodiment 77

The process defined in any one of embodiments 74-76, wherein the olefinmonomer comprises ethylene.

Embodiment 78

The process defined in any one of embodiments 74-77, wherein thecatalyst composition is contacted with ethylene and an olefin comonomercomprising a C₃-C₁₀ alpha-olefin.

Embodiment 79

The process defined in any one of embodiments 74-78, wherein thecatalyst composition is contacted with ethylene and an olefin comonomercomprising 1-butene, 1-hexene, 1-octene, or a mixture thereof.

Embodiment 80

The process defined in any one of embodiments 74-76, wherein the olefinmonomer comprises propylene.

Embodiment 81

The process defined in any one of embodiments 74-80, wherein thepolymerization reactor system comprises a batch reactor, a slurryreactor, a gas-phase reactor, a solution reactor, a high pressurereactor, a tubular reactor, an autoclave reactor, or a combinationthereof.

Embodiment 82

The process defined in any one of embodiments 74-81, wherein thepolymerization reactor system comprises a slurry reactor, a gas-phasereactor, a solution reactor, or a combination thereof.

Embodiment 83

The process defined in any one of embodiments 74-82, wherein thepolymerization reactor system comprises a loop slurry reactor.

Embodiment 84

The process defined in any one of embodiments 74-83, wherein thepolymerization reactor system comprises a single reactor.

Embodiment 85

The process defined in any one of embodiments 74-83, wherein thepolymerization reactor system comprises 2 reactors.

Embodiment 86

The process defined in any one of embodiments 74-83, wherein thepolymerization reactor system comprises more than 2 reactors.

Embodiment 87

The process defined in any one of embodiments 74-86, wherein the olefinpolymer comprises any olefin polymer disclosed herein.

Embodiment 88

The process defined in any one of embodiments 74-79 and 81-87, whereinthe olefin polymer is an ethylene homopolymer, an ethylene/1-butenecopolymer, an ethylene/1-hexene copolymer, or an ethylene/1-octenecopolymer.

Embodiment 89

The process defined in any one of embodiments 74-79 and 81-88, whereinthe olefin polymer is an ethylene/1-hexene copolymer.

Embodiment 90

The process defined in any one of embodiments 74-76 and 80-87, whereinthe olefin polymer is a polypropylene homopolymer or a propylene-basedcopolymer.

Embodiment 91

An olefin polymer produced by the olefin polymerization process definedin any one of embodiments 74-90.

Embodiment 92

An olefin polymer produced by the olefin polymerization process definedin any one of embodiments 74-90, wherein the olefin polymer containssubstantially no residual toluene, i.e., less than 5 ppm by weight.

Embodiment 93

An olefin polymer produced by the olefin polymerization process definedin any one of embodiments 74-90, wherein the olefin polymer containslower levels of residual solvents than that of an olefin polymerobtained using a catalyst system prepared by using toluene (and1-hexene, if used) instead of cyclohexene (and 1-hexene, if used), underthe same catalyst preparation and polymerization conditions.

Embodiment 94

An article comprising the olefin polymer defined in any one ofembodiments 91-93.

Embodiment 95

A method or forming or preparing an article of manufacture comprising anolefin polymer, the method comprising (i) performing the olefinpolymerization process defined in any one of embodiments 74-90 toproduce the olefin polymer, and (ii) forming the article of manufacturecomprising the olefin polymer, e.g., via any technique disclosed herein.

Embodiment 96

The article defined in embodiment 94 or 95, wherein the article is anagricultural film, an automobile part, a bottle, a drum, a fiber orfabric, a food packaging film or container, a food service article, afuel tank, a geomembrane, a household container, a liner, a moldedproduct, a medical device or material, a pipe, a sheet or tape, or atoy.

We claim:
 1. A process to produce a catalyst composition, the processcomprising: (i) contacting an activator-support and an organoaluminumcompound for a first period of time to form a precontacted mixture; and(ii) contacting the precontacted mixture with a second mixturecomprising cyclohexene and a metallocene compound for a second period oftime to form the catalyst composition.
 2. The process of claim 1,wherein: the first period of time is at least about 15 seconds; and anactivity of the catalyst composition is greater than that of a catalystsystem obtained by first combining the activator-support and the secondmixture, and then combining the organoaluminum compound, under the samepolymerization conditions.
 3. The process of claim 1, wherein: theactivator-support comprises a fluorided solid oxide, a sulfated solidoxide, a phosphated solid oxide, or a combination thereof; and themetallocene compound comprises a bridged zirconium or hafnium basedmetallocene compound with a cyclopentadienyl group and a fluorenylgroup.
 4. The process of claim 1, wherein an activity of the catalystcomposition is greater than that of a catalyst system obtained by usingtoluene instead of cyclohexene in the second mixture, under the samecatalyst preparation and polymerization conditions.
 5. The process ofclaim 1, wherein: a slurry of the activator-support in a hydrocarbondiluent is contacted with the organoaluminum compound in step (i); andthe second mixture comprising cyclohexene and the metallocene compoundis a solution.
 6. The process of claim 1, wherein the second mixturecomprises cyclohexene, 1-hexene, and the metallocene compound.
 7. Theprocess of claim 6, wherein: a weight ratio of 1-hexene:cyclohexene inthe second mixture is in a range from about 90:10 to about 20:80; and anactivity of the catalyst composition is greater than that of a catalystsystem obtained by using toluene and 1-hexene instead of cyclohexene and1-hexene in the second mixture, under the same catalyst preparation andpolymerization conditions.
 8. A process to produce a catalystcomposition, the process comprising contacting, in any order: (a) anactivator-support; (b) a mixture comprising cyclohexene and ametallocene compound; and (c) an organoaluminum compound; to produce thecatalyst composition.
 9. The process of claim 8, wherein: theactivator-support comprises a fluorided solid oxide, a sulfated solidoxide, a phosphated solid oxide, or a combination thereof; theorganoaluminum compound comprises trimethylaluminum, triethylaluminum,tri-n-propylaluminum, tri-n-butylaluminum, triisobutylaluminum, or anycombination thereof; and the metallocene compound comprises an unbridgedzirconium or hafnium based metallocene compound containing twocyclopentadienyl groups, two indenyl groups, or a cyclopentadienyl andan indenyl group.
 10. The process of claim 8, wherein an activity of thecatalyst composition is greater than that of a catalyst system obtainedby using toluene instead of cyclohexene in the mixture, under the samecatalyst preparation and polymerization conditions.
 11. The process ofclaim 8, wherein the mixture comprises cyclohexene, 1-hexene, and themetallocene compound.
 12. The process of claim 11, wherein: a weightratio of 1-hexene:cyclohexene in the mixture is in a range from about90:10 to about 50:50; and an activity of the catalyst composition isgreater than that of a catalyst system obtained by using toluene and1-hexene instead of cyclohexene and 1-hexene in the mixture, under thesame catalyst preparation and polymerization conditions.
 13. The processof claim 11, wherein the mixture comprising cyclohexene, 1-hexene, andthe metallocene compound has less precipitation of the metallocenecompound and/or the metallocene compound precipitates at a lowertemperature than that of a mixture containing toluene, 1-hexene, and themetallocene compound, when compared at the same metalloceneconcentration and the same weight ratio of 1-hexene:cyclohexene.